Method and apparatus for performing frame-based communication in unlicensed band in nr v2x

ABSTRACT

Provided are a method for performing wireless communication by a first device, and an apparatus for supporting same. The method may comprise: obtaining configuration information including at least one of information related to a first fixed frame period (FFP) or information related to a first FFP offset; determining a plurality of FFPs based on the configuration information; performing sensing related to the plurality of FFPs; determining whether a channel is idle within the plurality of FFPs based on the sensing related to the plurality of FFPs; and transmitting information related to a failure of the configuration information, based on a number of non-idle channels reaching a threshold.

CROSS-REFERENCE TO RELATED APPLICATION(S)

Pursuant to 35 U.S.C. § 119(e), this application claims the benefit ofU.S. Provisional Pat. Application No. 63/331,214, filed on Apr. 14,2022, the contents of which are all hereby incorporated by referenceherein in their entireties.

TECHNICAL FIELD

This disclosure relates to a wireless communication system.

BACKGROUND

Sidelink (SL) communication is a communication scheme in which a directlink is established between User Equipments (UEs) and the UEs exchangevoice and data directly with each other without intervention of anevolved Node B (eNB). SL communication is under consideration as asolution to the overhead of an eNB caused by rapidly increasing datatraffic. Vehicle-to-everything (V2X) refers to a communicationtechnology through which a vehicle exchanges information with anothervehicle, a pedestrian, an object having an infrastructure (or infra)established therein, and so on. The V2X may be divided into 4 types,such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I),vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). The V2Xcommunication may be provided via a PC5 interface and/or Uu interface.

Meanwhile, as a wider range of communication devices require largercommunication capacities, the need for mobile broadband communicationthat is more enhanced than the existing Radio Access Technology (RAT) isrising. Accordingly, discussions are made on services and user equipment(UE) that are sensitive to reliability and latency. And, a nextgeneration radio access technology that is based on the enhanced mobilebroadband communication, massive Machine Type Communication (MTC),Ultra-Reliable and Low Latency Communication (URLLC), and so on, may bereferred to as a new radio access technology (RAT) or new radio (NR).Herein, the NR may also support vehicle-to-everything (V2X)communication.

SUMMARY

Meanwhile, a UE attempting SL communication based on a frame in anunlicensed band may fail to occupy a channel within the frame due tocommunication of other UEs. If the UE continuously attempts to occupythe channel despite the failure of the UE to occupy the channel based onframe-related configuration information, battery consumption mayincrease due to unnecessary sensing of the UE, and quality of service(QoS) requirements of a packet to be transmitted may not be satisfied.

In one embodiment, provided is a method for performing wirelesscommunication by a first device. The method may comprise: obtainingconfiguration information including at least one of information relatedto a first fixed frame period (FFP) or information related to a firstFFP offset; determining a plurality of FFPs based on the configurationinformation; performing sensing related to the plurality of FFPs;determining whether a channel is idle within the plurality of FFPs basedon the sensing related to the plurality of FFPs; and transmittinginformation related to a failure of the configuration information, basedon a number of non-idle channels reaching a threshold.

In one embodiment, provided is a first device adapted to performwireless communication. The first device may comprise: at least onetransceiver; at least one processor; and at least one memory connectedto the at least one processor and storing instructions that, based onbeing executed by the at least one processor, perform operationscomprising: obtaining configuration information including at least oneof information related to a first fixed frame period (FFP) orinformation related to a first FFP offset; determining a plurality ofFFPs based on the configuration information; performing sensing relatedto the plurality of FFPs; determining whether a channel is idle withinthe plurality of FFPs based on the sensing related to the plurality ofFFPs; and transmitting information related to a failure of theconfiguration information, based on a number of non-idle channelsreaching a threshold.

In one embodiment, provided is a processing device adapted to control afirst device. The processing device may comprise: at least oneprocessor; and at least one memory connected to the at least oneprocessor and storing instructions that, based on being executed by theat least one processor, perform operations comprising: obtainingconfiguration information including at least one of information relatedto a first fixed frame period (FFP) or information related to a firstFFP offset; determining a plurality of FFPs based on the configurationinformation; performing sensing related to the plurality of FFPs;determining whether a channel is idle within the plurality of FFPs basedon the sensing related to the plurality of FFPs; and transmittinginformation related to a failure of the configuration information, basedon a number of non-idle channels reaching a threshold.

The reliability of SL communication can be secured while minimizing thepower consumption of the UE.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a structure of an NR system, based on an embodiment of thepresent disclosure.

FIG. 2 shows a radio protocol architecture, based on an embodiment ofthe present disclosure.

FIG. 3 shows a structure of a radio frame of an NR, based on anembodiment of the present disclosure.

FIG. 4 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure.

FIG. 5 shows an example of a BWP, based on an embodiment of the presentdisclosure.

FIG. 6 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure.

FIG. 7 shows three cast types, based on an embodiment of the presentdisclosure.

FIG. 8 shows an example of a wireless communication system supporting anunlicensed band, based on an embodiment of the present disclosure.

FIG. 9 shows a method of occupying resources in an unlicensed band,based on an embodiment of the present disclosure.

FIG. 10 shows a case in which a plurality of LBT-SBs are included in anunlicensed band, based on an embodiment of the present disclosure.

FIG. 11 shows CAP operations performed by a base station to transmit adownlink signal through an unlicensed band, based on an embodiment ofthe present disclosure.

FIG. 12 shows type 1 CAP operations performed by a UE to transmit anuplink signal, based on an embodiment of the present disclosure.

FIG. 13 shows a channel access procedure, based on an embodiment of thepresent disclosure.

FIG. 14 shows a procedure for a UE to perform channel occupation inunits of a frame in an unlicensed band, based on an embodiment of thepresent disclosure.

FIG. 15 shows a method for a UE to perform channel occupation in unitsof a frame in an unlicensed band, based on an embodiment of the presentdisclosure.

FIG. 16 shows a procedure for a UE to perform channel occupation inunits of a frame in an unlicensed band, based on an embodiment of thepresent disclosure.

FIG. 17 shows a method for performing wireless communication by a firstdevice, based on an embodiment of the present disclosure.

FIG. 18 shows a method for performing wireless communication by a seconddevice, based on an embodiment of the present disclosure.

FIG. 19 shows a communication system 1, based on an embodiment of thepresent disclosure.

FIG. 20 shows wireless devices, based on an embodiment of the presentdisclosure.

FIG. 21 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure.

FIG. 22 shows another example of a wireless device, based on anembodiment of the present disclosure.

FIG. 23 shows a hand-held device, based on an embodiment of the presentdisclosure.

FIG. 24 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure.

DETAILED DESCRIPTION

In the present disclosure, “A or B” may mean “only A”, “only B” or “bothA and B.” In other words, in the present disclosure, “A or B” may beinterpreted as “A and/or B”. For example, in the present disclosure, “A,B, or C” may mean “only A”, “only B”, “only C”, or “any combination ofA, B, C”.

A slash (/) or comma used in the present disclosure may mean “and/or”.For example, “A/B” may mean “A and/or B”. Accordingly, “A/B” may mean“only A”, “only B”, or “both A and B”. For example, “A, B, C” may mean“A, B, or C”.

In the present disclosure, “at least one of A and B” may mean “only A”,“only B”, or “both A and B”. In addition, in the present disclosure, theexpression “at least one of A or B” or “at least one of A and/or B” maybe interpreted as “at least one of A and B”.

In addition, in the present disclosure, “at least one of A, B, and C”may mean “only A”, “only B”, “only C”, or “any combination of A, B, andC”. In addition, “at least one of A, B, or C” or “at least one of A, B,and/or C” may mean “at least one of A, B, and C”.

In addition, a parenthesis used in the present disclosure may mean “forexample”. Specifically, when indicated as “control information (PDCCH)”,it may mean that “PDCCH” is proposed as an example of the “controlinformation”. In other words, the “control information” of the presentdisclosure is not limited to “PDCCH”, and “PDCCH” may be proposed as anexample of the “control information”. In addition, when indicated as“control information (i.e., PDCCH)”, it may also mean that “PDCCH” isproposed as an example of the “control information”.

In the following description, ‘when, if, or in case of’ may be replacedwith ‘based on’.

A technical feature described individually in one figure in the presentdisclosure may be individually implemented, or may be simultaneouslyimplemented.

In the present disclosure, a higher layer parameter may be a parameterwhich is configured, pre-configured or pre-defined for a UE. Forexample, a base station or a network may transmit the higher layerparameter to the UE. For example, the higher layer parameter may betransmitted through radio resource control (RRC) signaling or mediumaccess control (MAC) signaling.

The technology described below may be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and so on. TheCDMA may be implemented with a radio technology, such as universalterrestrial radio access (UTRA) or CDMA-2000. The TDMA may beimplemented with a radio technology, such as global system for mobilecommunications (GSM)/general packet ratio service (GPRS)/enhanced datarate for GSM evolution (EDGE). The OFDMA may be implemented with a radiotechnology, such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved UTRA(E-UTRA), and so on. IEEE 802.16 m is an evolved version of IEEE 802.16eand provides backward compatibility with a system based on the IEEE802.16e. The UTRAis part of a universal mobile telecommunication system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE) is part of an evolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTEuses the OFDMA in a downlink and uses the SC-FDMA in an uplink.LTE-advanced (LTE-A) is an evolution of the LTE.

5G NR is a successive technology of LTE-A corresponding to a newClean-slate type mobile communication system having the characteristicsof high performance, low latency, high availability, and so on. 5G NRmay use resources of all spectrum available for usage including lowfrequency bands of less than 1 GHz, middle frequency bands ranging from1 GHz to 10 GHz, high frequency (millimeter waves) of 24 GHz or more,and so on.

For clarity in the description, the following description will mostlyfocus on LTE-A or 5G NR. However, technical features according to anembodiment of the present disclosure will not be limited only to this.

FIG. 1 shows a structure of an NR system, based on an embodiment of thepresent disclosure. The embodiment of FIG. 1 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 1 , a next generation-radio access network (NG-RAN)may include a BS 20 providing a UE 10 with a user plane and controlplane protocol termination. For example, the BS 20 may include a nextgeneration-Node B (gNB) and/or an evolved-NodeB (eNB). For example, theUE 10 may be fixed or mobile and may be referred to as other terms, suchas a mobile station (MS), a user terminal (UT), a subscriber station(SS), a mobile terminal (MT), wireless device, and so on. For example,the BS may be referred to as a fixed station which communicates with theUE 10 and may be referred to as other terms, such as a base transceiversystem (BTS), an access point (AP), and so on.

The embodiment of FIG. 1 exemplifies a case where only the gNB isincluded. The BSs 20 may be connected to one another via Xn interface.The BS 20 may be connected to one another via 5th generation (5G) corenetwork (5GC) and NG interface. More specifically, the BSs 20 may beconnected to an access and mobility management function (AMF) 30 viaNG-C interface, and may be connected to a user plane function (UPF) 30via NG-U interface.

Layers of a radio interface protocol between the UE and the network canbe classified into a first layer (layer 1, L1), a second layer (layer 2,L2), and a third layer (layer 3, L3) based on the lower three layers ofthe open system interconnection (OSI) model that is well-known in thecommunication system. Among them, a physical (PHY) layer belonging tothe first layer provides an information transfer service by using aphysical channel, and a radio resource control (RRC) layer belonging tothe third layer serves to control a radio resource between the UE andthe network. For this, the RRC layer exchanges an RRC message betweenthe UE and the BS.

FIG. 2 shows a radio protocol architecture, based on an embodiment ofthe present disclosure. The embodiment of FIG. 2 may be combined withvarious embodiments of the present disclosure. Specifically, (a) of FIG.2 shows a radio protocol stack of a user plane for Uu communication, and(b) of FIG. 2 shows a radio protocol stack of a control plane for Uucommunication. (c) of FIG. 2 shows a radio protocol stack of a userplane for SL communication, and (d) of FIG. 2 shows a radio protocolstack of a control plane for SL communication.

Referring to FIG. 2 , a physical layer provides an upper layer with aninformation transfer service through a physical channel. The physicallayer is connected to a medium access control (MAC) layer which is anupper layer of the physical layer through a transport channel. Data istransferred between the MAC layer and the physical layer through thetransport channel. The transport channel is classified according to howand with what characteristics data is transmitted through a radiointerface.

Between different physical layers, i.e., a physical layer of atransmitter and a physical layer of a receiver, data are transferredthrough the physical channel. The physical channel is modulated using anorthogonal frequency division multiplexing (OFDM) scheme, and utilizestime and frequency as a radio resource.

The MAC layer provides services to a radio link control (RLC) layer,which is a higher layer of the MAC layer, via a logical channel. The MAClayer provides a function of mapping multiple logical channels tomultiple transport channels. The MAC layer also provides a function oflogical channel multiplexing by mapping multiple logical channels to asingle transport channel. The MAC layer provides data transfer servicesover logical channels.

The RLC layer performs concatenation, segmentation, and reassembly ofRadio Link Control Service Data Unit (RLC SDU). In order to ensurediverse quality of service (QoS) required by a radio bearer (RB), theRLC layer provides three types of operation modes, i.e., a transparentmode (TM), an unacknowledged mode (UM), and an acknowledged mode (AM).An AM RLC provides error correction through an automatic repeat request(ARQ).

A radio resource control (RRC) layer is defined only in the controlplane. The RRC layer serves to control the logical channel, thetransport channel, and the physical channel in association withconfiguration, reconfiguration and release of RBs. The RB is a logicalpath provided by the first layer (i.e., the physical layer or the PHYlayer) and the second layer (i.e., a MAC layer, an RLC layer, a packetdata convergence protocol (PDCP) layer, and a service data adaptationprotocol (SDAP) layer) for data delivery between the UE and the network.

Functions of a packet data convergence protocol (PDCP) layer in the userplane include user data delivery, header compression, and ciphering.Functions of a PDCP layer in the control plane include control-planedata delivery and ciphering/integrity protection.

A service data adaptation protocol (SDAP) layer is defined only in auser plane. The SDAP layer performs mapping between a Quality of Service(QoS) flow and a data radio bearer (DRB) and QoS flow ID (QFI) markingin both DL and UL packets.

The configuration of the RB implies a process for specifying a radioprotocol layer and channel properties to provide a particular serviceand for determining respective detailed parameters and operations. TheRB can be classified into two types, i.e., a signaling RB (SRB) and adata RB (DRB). The SRB is used as a path for transmitting an RRC messagein the control plane. The DRB is used as a path for transmitting userdata in the user plane.

When an RRC connection is established between an RRC layer of the UE andan RRC layer of the E-UTRAN, the UE is in an RRC_CONNECTED state, and,otherwise, the UE may be in an RRC_IDLE state. In case of the NR, anRRC_INACTIVE state is additionally defined, and a UE being in theRRC_INACTIVE state may maintain its connection with a core networkwhereas its connection with the BS is released.

Data is transmitted from the network to the UE through a downlinktransport channel. Examples of the downlink transport channel include abroadcast channel (BCH) for transmitting system information and adownlink-shared channel (SCH) for transmitting user traffic or controlmessages. Traffic of downlink multicast or broadcast services or thecontrol messages can be transmitted on the downlink-SCH or an additionaldownlink multicast channel (MCH). Data is transmitted from the UE to thenetwork through an uplink transport channel. Examples of the uplinktransport channel include a random access channel (RACH) fortransmitting an initial control message and an uplink SCH fortransmitting user traffic or control messages.

Examples of logical channels belonging to a higher channel of thetransport channel and mapped onto the transport channels include abroadcast channel (BCCH), a paging control channel (PCCH), a commoncontrol channel (CCCH), a multicast control channel (MCCH), a multicasttraffic channel (MTCH), etc.

FIG. 3 shows a structure of a radio frame of an NR, based on anembodiment of the present disclosure. The embodiment of FIG. 3 may becombined with various embodiments of the present disclosure.

Referring to FIG. 3 , in the NR, a radio frame may be used forperforming uplink and downlink transmission. A radio frame has a lengthof 10 ms and may be defined to be configured of two half-frames (HFs). Ahalf-frame may include five 1 ms subframes (SFs). A subframe (SF) may bedivided into one or more slots, and the number of slots within asubframe may be determined based on subcarrier spacing (SCS). Each slotmay include 12 or 14 OFDM(A) symbols according to a cyclic prefix (CP).

In case of using a normal CP, each slot may include 14 symbols. In caseof using an extended CP, each slot may include 12 symbols. Herein, asymbol may include an OFDM symbol (or CP-OFDM symbol) and a SingleCarrier-FDMA (SC-FDMA) symbol (or Discrete Fourier Transform-spread-OFDM(DFT-s-OFDM) symbol).

Table 1 shown below represents an example of a number of symbols perslot (N^(slot) _(symb)), a number slots per frame (N^(frame,u) _(slot)),and a number of slots per subframe (N^(subframe,u) _(slot)) based on anSCS configuration (u), in a case where a normal CP is used.

TABLE 1 SCS (15^(∗)2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 15 KHz (u=0) 14 10 1 30 KHz (u=1) 14 20 2 60 KHz(u=2) 14 40 4 120 KHz (u=3) 14 80 8 240 KHz (u=4) 14 160 16

Table 2 shows an example of a number of symbols per slot, a number ofslots per frame, and a number of slots per subframe based on the SCS, ina case where an extended CP is used.

TABLE 2 SCS (15^(∗)2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 60 KHz (u=2) 12 40 4

In an NR system, OFDM(A) numerologies (e.g., SCS, CP length, and so on)between multiple cells being integrate to one UE may be differentlyconfigured. Accordingly, a (absolute time) duration (or section) of atime resource (e.g., subframe, slot or TTI) (collectively referred to asa time unit (TU) for simplicity) being configured of the same number ofsymbols may be differently configured in the integrated cells.

In the NR, multiple numerologies or SCSs for supporting diverse 5Gservices may be supported. For example, in case an SCS is 15 kHz, a widearea of the conventional cellular bands may be supported, and, in casean SCS is 30 kHz/60kHz a dense-urban, lower latency, wider carrierbandwidth may be supported. In case the SCS is 60 kHz or higher, abandwidth that is greater than 24.25 GHz may be used in order toovercome phase noise.

An NR frequency band may be defined as two different types of frequencyranges. The two different types of frequency ranges may be FR1 and FR2.The values of the frequency ranges may be changed (or varied), and, forexample, the two different types of frequency ranges may be as shownbelow in Table 3. Among the frequency ranges that are used in an NRsystem, FR1 may mean a “sub 6 GHz range”, and FR2 may mean an “above 6GHz range” and may also be referred to as a millimeter wave (mmW).

TABLE 3 Frequency Range designation Corresponding frequency rangeSubcarrier Spacing (SCS) FR1 450 MHz - 6000 MHz 15, 30, 60 kHz FR2 24250MHz - 52600 MHz 60, 120, 240 kHz

As described above, the values of the frequency ranges in the NR systemmay be changed (or varied). For example, as shown below in Table 4, FR1may include a band within a range of 410 MHz to 7125 MHz. Morespecifically, FR1 may include a frequency band of 6 GHz (or 5850, 5900,5925 MHz, and so on) and higher. For example, a frequency band of 6 GHz(or 5850, 5900, 5925 MHz, and so on) and higher being included in FR1mat include an unlicensed band. The unlicensed band may be used fordiverse purposes, e.g., the unlicensed band for vehicle-specificcommunication (e.g., automated driving).

TABLE 4 Frequency Range designation Corresponding frequency rangeSubcarrier Spacing (SCS) FR1 410 MHz - 7125 MHz 15, 30, 60 kHz FR2 24250MHz - 52600 MHz 60, 120, 240 kHz

FIG. 4 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure. The embodiment of FIG. 4 may becombined with various embodiments of the present disclosure.

Referring to FIG. 4 , a slot includes a plurality of symbols in a timedomain. For example, in case of a normal CP, one slot may include 14symbols. However, in case of an extended CP, one slot may include 12symbols. Alternatively, in case of a normal CP, one slot may include 7symbols. However, in case of an extended CP, one slot may include 6symbols.

A carrier includes a plurality of subcarriers in a frequency domain. AResource Block (RB) may be defined as a plurality of consecutivesubcarriers (e.g., 12 subcarriers) in the frequency domain. A BandwidthPart (BWP) may be defined as a plurality of consecutive (Physical)Resource Blocks ((P)RBs) in the frequency domain, and the BWP maycorrespond to one numerology (e.g., SCS, CP length, and so on). Acarrier may include a maximum of N number BWPs (e.g., 5 BWPs). Datacommunication may be performed via an activated BWP. Each element may bereferred to as a Resource Element (RE) within a resource grid and onecomplex symbol may be mapped to each element.

Hereinafter, a bandwidth part (BWP) and a carrier will be described.

The BWP may be a set of consecutive physical resource blocks (PRBs) in agiven numerology. The PRB may be selected from consecutive sub-sets ofcommon resource blocks (CRBs) for the given numerology on a givencarrier

For example, the BWP may be at least any one of an active BWP, aninitial BWP, and/or a default BWP. For example, the UE may not monitordownlink radio link quality in a DL BWP other than an active DL BWP on aprimary cell (PCell). For example, the UE may not receive PDCCH,physical downlink shared channel (PDSCH), or channel state information -reference signal (CSI-RS) (excluding RRM) outside the active DL BWP. Forexample, the UE may not trigger a channel state information (CSI) reportfor the inactive DL BWP. For example, the UE may not transmit physicaluplink control channel (PUCCH) or physical uplink shared channel (PUSCH)outside an active UL BWP. For example, in a downlink case, the initialBWP may be given as a consecutive RB set for a remaining minimum systeminformation (RMSI) control resource set (CORESET) (configured byphysical broadcast channel (PBCH)). For example, in an uplink case, theinitial BWP may be given by system information block (SIB) for a randomaccess procedure. For example, the default BWP may be configured by ahigher layer. For example, an initial value of the default BWP may be aninitial DL BWP. For energy saving, if the UE fails to detect downlinkcontrol information (DCI) during a specific period, the UE may switchthe active BWP of the UE to the default BWP.

Meanwhile, the BWP may be defined for SL. The same SL BWP may be used intransmission and reception. For example, a transmitting UE may transmita SL channel or a SL signal on a specific BWP, and a receiving UE mayreceive the SL channel or the SL signal on the specific BWP. In alicensed carrier, the SL BWP may be defined separately from a Uu BWP,and the SL BWP may have configuration signaling separate from the UuBWP. For example, the UE may receive a configuration for the SL BWP fromthe BS/network. For example, the UE may receive a configuration for theUu BWP from the BS/network. The SL BWP may be (pre-)configured in acarrier with respect to an out-of-coverage NR V2X UE and an RRC_IDLE UE.For the UE in the RRC_CONNECTED mode, at least one SL BWP may beactivated in the carrier.

FIG. 5 shows an example of a BWP, based on an embodiment of the presentdisclosure. The embodiment of FIG. 5 may be combined with variousembodiments of the present disclosure. It is assumed in the embodimentof FIG. 5 that the number of BWPs is 3.

Referring to FIG. 5 , a common resource block (CRB) may be a carrierresource block numbered from one end of a carrier band to the other endthereof. In addition, the PRB may be a resource block numbered withineach BWP. A point A may indicate a common reference point for a resourceblock grid.

The BWP may be configured by a point A, an offset N^(start) _(BWP) fromthe point A, and a bandwidth N^(size) _(BWP). For example, the point Amay be an external reference point of a PRB of a carrier in which asubcarrier 0 of all numerologies (e.g., all numerologies supported by anetwork on that carrier) is aligned. For example, the offset may be aPRB interval between a lowest subcarrier and the point A in a givennumerology. For example, the bandwidth may be the number of PRBs in thegiven numerology.

Hereinafter, V2X or SL communication will be described.

A sidelink synchronization signal (SLSS) may include a primary sidelinksynchronization signal (PSSS) and a secondary sidelink synchronizationsignal (SSSS), as a SL-specific sequence. The PSSS may be referred to asa sidelink primary synchronization signal (S-PSS), and the SSSS may bereferred to as a sidelink secondary synchronization signal (S-SSS). Forexample, length-127 M-sequences may be used for the S-PSS, andlength-127 gold sequences may be used for the S-SSS. For example, a UEmay use the S-PSS for initial signal detection and for synchronizationacquisition. For example, the UE may use the S-PSS and the S-SSS foracquisition of detailed synchronization and for detection of asynchronization signal ID.

A physical sidelink broadcast channel (PSBCH) may be a (broadcast)channel for transmitting default (system) information which must befirst known by the UE before SL signal transmission/reception. Forexample, the default information may be information related to SLSS, aduplex mode (DM), a time division duplex (TDD) uplink/downlink (UL/DL)configuration, information related to a resource pool, a type of anapplication related to the SLSS, a subframe offset, broadcastinformation, or the like. For example, for evaluation of PSBCHperformance, in NR V2X, a payload size of the PSBCH may be 56 bitsincluding 24-bit cyclic redundancy check (CRC).

The S-PSS, the S-SSS, and the PSBCH may be included in a block format(e.g., SL synchronization signal (SS)/PSBCH block, hereinafter,sidelink-synchronization signal block (S-SSB)) supporting periodicaltransmission. The S-SSB may have the same numerology (i.e., SCS and CPlength) as a physical sidelink control channel (PSCCH)/physical sidelinkshared channel (PSSCH) in a carrier, and a transmission bandwidth mayexist within a (pre-)configured sidelink (SL) BWP. For example, theS-SSB may have a bandwidth of 11 resource blocks (RBs). For example, thePSBCH may exist across 11 RBs. In addition, a frequency position of theS-SSB may be (pre-)configured. Accordingly, the UE does not have toperform hypothesis detection at frequency to discover the S-SSB in thecarrier.

FIG. 6 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure. The embodiment of FIG. 6 may be combined with variousembodiments of the present disclosure. In various embodiments of thepresent disclosure, the transmission mode may be called a mode or aresource allocation mode. Hereinafter, for convenience of explanation,in LTE, the transmission mode may be called an LTE transmission mode. InNR, the transmission mode may be called an NR resource allocation mode.

For example, (a) of FIG. 6 shows a UE operation related to an LTEtransmission mode 1 or an LTE transmission mode 3. Alternatively, forexample, (a) of FIG. 6 shows a UE operation related to an NR resourceallocation mode 1. For example, the LTE transmission mode 1 may beapplied to general SL communication, and the LTE transmission mode 3 maybe applied to V2X communication.

For example, (b) of FIG. 6 shows a UE operation related to an LTEtransmission mode 2 or an LTE transmission mode 4. Alternatively, forexample, (b) of FIG. 6 shows a UE operation related to an NR resourceallocation mode 2.

Referring to (a) of FIG. 6 , in the LTE transmission mode 1, the LTEtransmission mode 3, or the NR resource allocation mode 1, a basestation may schedule SL resource(s) to be used by a UE for SLtransmission. For example, in step S600, a base station may transmitinformation related to SL resource(s) and/or information related to ULresource(s) to a first UE. For example, the UL resource(s) may includePUCCH resource(s) and/or PUSCH resource(s). For example, the ULresource(s) may be resource(s) for reporting SL HARQ feedback to thebase station.

For example, the first UE may receive information related to dynamicgrant (DG) resource(s) and/or information related to configured grant(CG) resource(s) from the base station. For example, the CG resource(s)may include CG type 1 resource(s) or CG type 2 resource(s). In thepresent disclosure, the DG resource(s) may be resource(s)configured/allocated by the base station to the first UE through adownlink control information (DCI). In the present disclosure, the CGresource(s) may be (periodic) resource(s) configured/allocated by thebase station to the first UE through a DCI and/or an RRC message. Forexample, in the case of the CG type 1 resource(s), the base station maytransmit an RRC message including information related to CG resource(s)to the first UE. For example, in the case of the CG type 2 resource(s),the base station may transmit an RRC message including informationrelated to CG resource(s) to the first UE, and the base station maytransmit a DCI related to activation or release of the CG resource(s) tothe first UE.

In step S610, the first UE may transmit a PSCCH (e.g., sidelink controlinformation (SCI) or 1^(st)-stage SCI) to a second UE based on theresource scheduling. In step S620, the first UE may transmit a PSSCH(e.g., 2^(nd)-stage SCI, MAC PDU, data, etc.) related to the PSCCH tothe second UE. In step S630, the first UE may receive a PSFCH related tothe PSCCH/PSSCH from the second UE. For example, HARQ feedbackinformation (e.g., NACK information or ACK information) may be receivedfrom the second UE through the PSFCH. In step S640, the first UE maytransmit/report HARQ feedback information to the base station throughthe PUCCH or the PUSCH. For example, the HARQ feedback informationreported to the base station may be information generated by the firstUE based on the HARQ feedback information received from the second UE.For example, the HARQ feedback information reported to the base stationmay be information generated by the first UE based on a pre-configuredrule. For example, the DCI may be a DCI for SL scheduling. For example,a format of the DCI may be a DCI format 3_0 or a DCI format 3_1.

Referring to (b) of FIG. 6 , in the LTE transmission mode 2, the LTEtransmission mode 4, or the NR resource allocation mode 2, a UE maydetermine SL transmission resource(s) within SL resource(s) configuredby a base station/network or pre-configured SL resource(s). For example,the configured SL resource(s) or the pre-configured SL resource(s) maybe a resource pool. For example, the UE may autonomously select orschedule resource(s) for SL transmission. For example, the UE mayperform SL communication by autonomously selecting resource(s) withinthe configured resource pool. For example, the UE may autonomouslyselect resource(s) within a selection window by performing a sensingprocedure and a resource (re)selection procedure. For example, thesensing may be performed in a unit of subchannel(s). For example, instep S610, a first UE which has selected resource(s) from a resourcepool by itself may transmit a PSCCH (e.g., sidelink control information(SCI) or 1^(st)-stage SCI) to a second UE by using the resource(s). Instep S620, the first UE may transmit a PSSCH (e.g., 2^(nd)-stage SCI,MAC PDU, data, etc.) related to the PSCCH to the second UE. In stepS630, the first UE may receive a PSFCH related to the PSCCH/PSSCH fromthe second UE.

Referring to (a) or (b) of FIG. 6 , for example, the first UE maytransmit a SCI to the second UE through the PSCCH. Alternatively, forexample, the first UE may transmit two consecutive SCIs (e.g., 2-stageSCI) to the second UE through the PSCCH and/or the PSSCH. In this case,the second UE may decode two consecutive SCIs (e.g., 2-stage SCI) toreceive the PSSCH from the first UE. In the present disclosure, a SCItransmitted through a PSCCH may be referred to as a 1^(st) SCI, a firstSCI, a 1^(st)-stage SCI or a 1^(st)-stage SCI format, and a SCItransmitted through a PSSCH may be referred to as a 2^(nd) SCI, a secondSCI, a 2^(nd)-stage SCI or a 2^(nd)-stage SCI format. For example, the1^(st)-stage SCI format may include a SCI format 1-A, and the2^(nd)-stage SCI format may include a SCI format 2-A and/or a SCI format2-B.

Hereinafter, an example of SCI format 1-A will be described.

SCI format 1-A is used for the scheduling of PSSCH and 2nd-stage-SCI onPSSCH.

The following information is transmitted by means of the SCI format 1-A:

-   Priority 3 bits-   Frequency resource assignment ceiling (log₂(N^(SL)    _(subChannel)(N^(SL) _(subChannel)+1)/2)) bits when the value of the    higher layer parameter sl-MaxNumPerReserve is configured to 2;    otherwise ceiling log₂(N^(SL) _(subChannel)(N^(SL)    _(subChannel)+1)(2N^(SL) _(subChannel)+1)/6) bits when the value of    the higher layer parameter sl-MaxNumPerReserve is configured to 3-   Time resource assignment 5 bits when the value of the higher layer    parameter sl-MaxNumPerReserve is configured to 2; otherwise 9 bits    when the value of the higher layer parameter sl-MaxNumPerReserve is    configured to 3-   Resource reservation period ceiling (log₂N_(rsv)_period) bits, where    N_(rsv_period) is the number of entries in the higher layer    parameter sl-ResourceReservePeriodList, if higher layer parameter    sl-MultiReserveResource is configured; 0 bit otherwise-   DMRS pattern ceiling (log₂ N_(pattern))bits, where N_(pattern) is    the number of DMRS patterns configured by higher layer parameter    sl-PSSCH-DMRS-TimePatternList-   2^(nd)-stage SCI format - 2 bits as defined in Table 5-   Beta_offset indicator 2 bits as provided by higher layer parameter    sl-BetaOffsets2ndSCI-   Number of DMRS port 1 bit as defined in Table 6-   Modulation and coding scheme 5 bits-   Additional MCS table indicator 1 bit if one MCS table is configured    by higher layer parameter sl-Additional-MCS-Table; 2 bits if two MCS    tables are configured by higher layer parameter sl-    Additional-MCS-Table; 0 bit otherwise-   PSFCH overhead indication 1 bit if higher layer parameter    sl-PSFCH-Period = 2 or 4; 0 bit otherwise-   Reserved a number of bits as determined by higher layer parameter    sl-NumReservedBits, with value set to zero.

TABLE 5 Value of 2nd-stage SCI format field 2nd-stage SCI format 00 SCIformat 2-A 01 SCI format 2-B 10 Reserved 11 Reserved

TABLE 6 Value of the Number of DMRS port field Antenna ports 0 1000 11000 and 1001

Hereinafter, an example of SCI format 2-A will be described.

SCI format 2-A is used for the decoding of PSSCH, with HARQ operationwhen HARQ-ACK information includes ACK or NACK, when HARQ-ACKinformation includes only NACK, or when there is no feedback of HARQ-ACKinformation.

The following information is transmitted by means of the SCI format 2-A:

-   HARQ process number 4 bits-   New data indicator 1 bit-   Redundancy version 2 bits-   Source ID 8 bits-   Destination ID 16 bits-   HARQ feedback enabled/disabled indicator 1 bit-   Cast type indicator 2 bits as defined in Table 7-   CSI request 1 bit

TABLE 7 Value of Cast type indicator Cast type 00 Broadcast 01 Groupcastwhen HARQ-ACK information includes ACK or NACK 10 Unicast 11 Groupcastwhen HARQ-ACK information includes only NACK

Hereinafter, an example of SCI format 2-B will be described.

SCI format 2-B is used for the decoding of PSSCH, with HARQ operationwhen HARQ-ACK information includes only NACK, or when there is nofeedback of HARQ-ACK information.

The following information is transmitted by means of the SCI format 2-B:

-   HARQ process number 4 bits-   New data indicator 1 bit-   Redundancy version 2 bits-   Source ID 8 bits-   Destination ID 16 bits-   HARQ feedback enabled/disabled indicator 1 bit-   Zone ID 12 bits-   Communication range requirement 4 bits determined by higher layer    parameter sl-ZoneConfigMCR-Index

Referring to (a) or (b) of FIG. 6 , in step S630, the first UE mayreceive the PSFCH. For example, the first UE and the second UE maydetermine a PSFCH resource, and the second UE may transmit HARQ feedbackto the first UE using the PSFCH resource.

Referring to (a) of FIG. 6 , in step S640, the first UE may transmit SLHARQ feedback to the base station through the PUCCH and/or the PUSCH.

FIG. 7 shows three cast types, based on an embodiment of the presentdisclosure. The embodiment of FIG. 7 may be combined with variousembodiments of the present disclosure. Specifically, (a) of FIG. 7 showsbroadcast-type SL communication, (b) of FIG. 7 shows unicast type-SLcommunication, and (c) of FIG. 7 shows groupcast-type SL communication.In case of the unicast-type SL communication, a UE may performone-to-one communication with respect to another UE. In case of thegroupcast-type SL transmission, the UE may perform SL communication withrespect to one or more UEs in a group to which the UE belongs. Invarious embodiments of the present disclosure, SL groupcastcommunication may be replaced with SL multicast communication, SLone-to-many communication, or the like.

Hereinafter, a hybrid automatic repeat request (HARQ) procedure will bedescribed.

For example, the SL HARQ feedback may be enabled for unicast. In thiscase, in a non-code block group (non-CBG) operation, if the receiving UEdecodes a PSCCH of which a target is the receiving UE and if thereceiving UE successfully decodes a transport block related to thePSCCH, the receiving UE may generate HARQ-ACK. In addition, thereceiving UE may transmit the HARQ-ACK to the transmitting UE.Otherwise, if the receiving UE cannot successfully decode the transportblock after decoding the PSCCH of which the target is the receiving UE,the receiving UE may generate the HARQ-NACK. In addition, the receivingUE may transmit HARQ-NACK to the transmitting UE.

For example, the SL HARQ feedback may be enabled for groupcast. Forexample, in the non-CBG operation, two HARQ feedback options may besupported for groupcast.

(1) Groupcast option 1: After the receiving UE decodes the PSCCH ofwhich the target is the receiving UE, if the receiving UE fails indecoding of a transport block related to the PSCCH, the receiving UE maytransmit HARQ-NACK to the transmitting UE through a PSFCH. Otherwise, ifthe receiving UE decodes the PSCCH of which the target is the receivingUE and if the receiving UE successfully decodes the transport blockrelated to the PSCCH, the receiving UE may not transmit the HARQ-ACK tothe transmitting UE.

(2) Groupcast option 2: After the receiving UE decodes the PSCCH ofwhich the target is the receiving UE, if the receiving UE fails indecoding of the transport block related to the PSCCH, the receiving UEmay transmit HARQ-NACK to the transmitting UE through the PSFCH. Inaddition, if the receiving UE decodes the PSCCH of which the target isthe receiving UE and if the receiving UE successfully decodes thetransport block related to the PSCCH, the receiving UE may transmit theHARQ-ACK to the transmitting UE through the PSFCH.

For example, if the groupcast option 1 is used in the SL HARQ feedback,all UEs performing groupcast communication may share a PSFCH resource.For example, UEs belonging to the same group may transmit HARQ feedbackby using the same PSFCH resource.

For example, if the groupcast option 2 is used in the SL HARQ feedback,each UE performing groupcast communication may use a different PSFCHresource for HARQ feedback transmission. For example, UEs belonging tothe same group may transmit HARQ feedback by using different PSFCHresources.

In the present disclosure, HARQ-ACK may be referred to as ACK, ACKinformation, or positive-ACK information, and HARQ-NACK may be referredto as NACK, NACK information, or negative-ACK information.

Meanwhile, in the conventional unlicensed spectrum (NR-U), acommunication method between a UE and a base station is supported in anunlicensed band. In addition, a mechanism for supporting communicationin an unlicensed band between sidelink UEs is planned to be supported inRel-18.

In the present disclosure, a channel may refer to a set of frequencydomain resources in which Listen-Before-Talk (LBT) is performed. InNR-U, the channel may refer to an LBT bandwidth with 20 MHz and may havethe same meaning as an RB set. For example, the RB set may be defined insection 7 of 3GPP TS 38.214 V17.0.0.

In the present disclosure, channel occupancy (CO) may refer totime/frequency domain resources obtained by the base station or the UEafter LBT success.

In the present disclosure, channel occupancy time (COT) may refer totime domain resources obtained by the base station or the UE after LBTsuccess. It may be shared between the base station (or the UE) and theUE (or the base station) that obtained the CO, and this may be referredto as COT sharing. Depending on the initiating device, this may bereferred to as gNB-initiated COT or UE-initiated COT.

Hereinafter, a wireless communication system supporting an unlicensedband/shared spectrum will be described.

FIG. 8 shows an example of a wireless communication system supporting anunlicensed band, based on an embodiment of the present disclosure. Forexample, FIG. 8 may include an unlicensed spectrum (NR-U) wirelesscommunication system. The embodiment of FIG. 8 may be combined withvarious embodiments of the present disclosure.

In the following description, a cell operating in a licensed band(hereinafter, L-band) may be defined as an L-cell, and a carrier of theL-cell may be defined as a (DL/UL/SL) LCC. In addition, a cell operatingin an unlicensed band (hereinafter, U-band) may be defined as a U-cell,and a carrier of the U-cell may be defined as a (DL/UL/SL) UCC. Thecarrier/carrier-frequency of a cell may refer to the operating frequency(e.g., center frequency) of the cell. A cell/carrier (e.g., CC) iscommonly called a cell.

When the base station and the UE transmit and receive signals oncarrier-aggregated LCC and UCC as shown in (a) of FIG. 8 , the LCC andthe UCC may be configured as a primary CC (PCC) and a secondary CC(SCC), respectively. The base station and the UE may transmit andreceive signals on one UCC or on a plurality of carrier-aggregated UCCsas shown in (b) of FIG. 8 . In other words, the base station and the UEmay transmit and receive signals only on UCC(s) without using any LCC.For a standalone operation, PRACH transmission, PUCCH transmission,PUSCH transmission, SRS transmission, etc. may be supported on a UCell.

In the embodiment of FIG. 8 , the base station may be replaced with theUE. In this case, for example, PSCCH transmission, PSSCH transmission,PSFCH transmission, S-SSB transmission, etc. may be supported on aUCell.

Unless otherwise noted, the definitions below are applicable to thefollowing terminologies used in the present disclosure.

-   Channel: a carrier or a part of a carrier composed of a contiguous    set of RBs in which a channel access procedure is performed in a    shared spectrum.-   Channel access procedure (CAP): a procedure of assessing channel    availability based on sensing before signal transmission in order to    determine whether other communication node(s) are using a channel. A    basic sensing unit is a sensing slot with a duration of T_(sl) = 9    us. The base station or the UE senses a channel during a sensing    slot duration. If power detected for at least 4 us within the    sensing slot duration is less than an energy detection threshold    X_(thresh), the sensing slot duration T_(sl) is considered to be    idle. Otherwise, the sensing slot duration T_(sl) = 9 us is    considered to be busy. CAP may also be referred to as listen before    talk (LBT).-   Channel occupancy: transmission(s) on channel(s) by the base    station/UE after a channel access procedure.-   Channel occupancy time (COT): a total time during which the base    station/UE and any base station/UE(s) sharing channel occupancy can    perform transmission(s) on a channel after the base station/UE    perform a channel access procedure. In the case of determining COT,    if a transmission gap is less than or equal to 25 us, the gap    duration may be counted in the COT. The COT may be shared for    transmission between the base station and corresponding UE(s).-   DL transmission burst: a set of transmissions without any gap    greater than 16 us from the base station. Transmissions from the    base station, which are separated by a gap exceeding 16 us are    considered as separate DL transmission bursts. The base station may    perform transmission(s) after a gap without sensing channel    availability within a DL transmission burst.-   UL or SL transmission burst: a set of transmissions without any gap    greater than 16 us from the UE. Transmissions from the UE, which are    separated by a gap exceeding 16 us are considered as separate UL or    SL transmission bursts. The UE may perform transmission(s) after a    gap without sensing channel availability within a UL or SL    transmission burst.-   Discovery burst: a DL transmission burst including a set of    signal(s) and/or channel(s) confined within a window and associated    with a duty cycle. In the LTE-based system, the discovery burst may    be transmission(s) initiated by the base station, which includes    PSS, an SSS, and cell-specific RS (CRS) and further includes    non-zero power CSI-RS. In the NR-based system, the discover burst    may be transmission(s) initiated by the base station, which includes    at least an SS/PBCH block and further includes CORESET for a PDCCH    scheduling a PDSCH carrying SIB 1, the PDSCH carrying SIB1, and/or    non-zero power CSI-RS.

FIG. 9 shows a method of occupying resources in an unlicensed band,based on an embodiment of the present disclosure. The embodiment of FIG.9 may be combined with various embodiments of the present disclosure.

Referring to FIG. 9 , a communication node (e.g., base station, UE)within an unlicensed band should determine whether other communicationnode(s) is using a channel before signal transmission. To this end, thecommunication node within the unlicensed band may perform a channelaccess procedure (CAP) to access channel(s) on which transmission(s) isperformed. The channel access procedure may be performed based onsensing. For example, the communication node may perform carrier sensing(CS) before transmitting signals so as to check whether othercommunication node(s) perform signal transmission. When the othercommunication node(s) perform no signal transmission, it is said thatclear channel assessment (CCA) is confirmed. If a CCA threshold (e.g.,X_(Thresh)) is predefined or configured by a higher layer (e.g., RRC),the communication node may determine that the channel is busy if thedetected channel energy is higher than the CCA threshold. Otherwise, thecommunication node may determine that the channel is idle. If it isdetermined that the channel is idle, the communication node may startthe signal transmission in the unlicensed band. The CAP may be replacedwith the LBT.

Table 8 shows an example of the channel access procedure (CAP) supportedin NR-U.

TABLE 8 Type Explanation DL Type 1 CAP CAP with random back-off - timeduration spanned by the sensing slots that are sensed to be idle beforea downlink transmission(s) is random UL or SL Type 1 CAP CAP with randomback-off - time duration spanned by the sensing slots that are sensed tobe idle before an uplink or sidelink transmission(s) is random Type 2CAP - Type 2A, 2B, 2C CAP without random back-off - time durationspanned by sensing slots that are sensed to be idle before an uplink orsidelink transmission(s) is deterministic

Referring to Table 8, the LBT type or CAP for DL/UL/SL transmission maybe defined. However, Table 8 is only an example, and a new type or CAPmay be defined in a similar manner. For example, the type 1 (alsoreferred to as Cat-4 LBT) may be a random back-off based channel accessprocedure. For example, in the case of Cat-4, the contention window maychange. For example, the type 2 can be performed in case of COT sharingwithin COT acquired by the base station (gNB) or the UE.

Hereinafter, LBT-SubBand (SB) (or RB set) will be described.

In a wireless communication system supporting an unlicensed band, onecell (or carrier (e.g., CC)) or BWP configured for the UE may have awideband having a larger bandwidth (BW) than in legacy LTE. However, aBW requiring CCA based on an independent LBT operation may be limitedaccording to regulations. Let a subband (SB) in which LBT isindividually performed be defined as an LBT-SB. Then, a plurality ofLBT-SBs may be included in one wideband cell/BWP. A set of RBs includedin an LBT-SB may be configured by higher-layer (e.g., RRC) signaling.Accordingly, one or more LBT-SBs may be included in one cell/BWP basedon (i) the BW of the cell/BWP and (ii) RB set allocation information.

FIG. 10 shows a case in which a plurality of LBT-SBs are included in anunlicensed band, based on an embodiment of the present disclosure. Theembodiment of FIG. 10 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 10 , a plurality of LBT-SBs may be included in the BWPof a cell (or carrier). An LBT-SB may have, for example, a 20-MHz band.The LBT-SB may include a plurality of contiguous (P)RBs in the frequencydomain, and thus may be referred to as a (P)RB set. While not shown, aguard band (GB) may be interposed between LBT-SBs. Accordingly, the BWPmay be configured in the form of {LBT-SB #0 (RB set #0)+GB #0+LBT-SB #1(RB set #1+GB #1) + ... +LBT-SB #(K-1) (RB set (#K-1))}. Forconvenience, LBT-SB/RB indexes may be configured/defined in anincreasing order from the lowest frequency to the highest frequency.

Hereinafter, a channel access priority class (CAPC) will be described.

The CAPCs of MAC CEs and radio bearers may be fixed or configured tooperate in FR1:

-   Fixed to lowest priority for padding buffer status report (BSR) and    recommended bit rate MAC CE;-   Fixed to highest priority for SRB0, SRB1, SRB3 and other MAC CEs;-   Configured by the base station for SRB2 and DRB.

When selecting a CAPC of a DRB, the base station considers fairnessbetween other traffic types and transmissions while considering 5QI ofall QoS flows multiplexed to the corresponding DRB. Table 9 shows whichCAPC should be used for standardized 5QI, that is, a CAPC to be used fora given QoS flow. For standardized 5QI, CAPCs are defined as shown inthe table below, and for non-standardized 5QI, the CAPC with the bestQoS characteristics should be used.

TABLE 9 CAPC 5QI 1 1, 3, 5, 65, 66, 67, 69, 70, 79, 80, 82, 83, 84, 85 22, 7, 71 3 4, 6, 8, 9, 72, 73, 74, 76 4 - NOTE: A lower CAPC valueindicates a higher priority.

Hereinafter, a method of transmitting a downlink signal through anunlicensed band will be described. For example, a method of transmittinga downlink signal through an unlicensed band may be applied to a methodof transmitting a sidelink signal through an unlicensed band.

The base station may perform one of the following channel accessprocedures (e.g., CAP) for downlink signal transmission in an unlicensedband.

(1) Type 1 Downlink (DL) CAP Method

In the type 1 DL CAP, the length of a time duration spanned by sensingslots sensed to be idle before transmission(s) may be random. The type 1DL CAP may be applied to the following transmissions:

-   Transmission(s) initiated by the base station including (i) a    unicast PDSCH with user plane data or (ii) the unicast PDSCH with    user plane data and a unicast PDCCH scheduling user plane data, or-   Transmission(s) initiated by the base station including (i) a    discovery burst only or (ii) a discovery burst multiplexed with    non-unicast information.

FIG. 11 shows CAP operations performed by a base station to transmit adownlink signal through an unlicensed band, based on an embodiment ofthe present disclosure. The embodiment of FIG. 11 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 11 , the base station may sense whether a channel isidle for sensing slot durations of a defer duration T_(d). Then, if acounter N is zero, the base station may perform transmission (S134). Inthis case, the base station may adjust the counter N by sensing thechannel for additional sensing slot duration(s) according to thefollowing steps:

Step 1) (S120) The base station sets N to N_(init) (N= N_(init)), whereN_(init) is a random number uniformly distributed between 0 and CW_(p).Then, step 4 proceeds.

Step 2) (S140) If N>0 and the base station determines to decrease thecounter, the base station sets N to N-1 (N=N-1).

Step 3) (S150) The base station senses the channel for the additionalsensing slot duration. If the additional sensing slot duration is idle(Y), step 4 proceeds. Otherwise (N), step 5 proceeds.

Step 4) (S130) If N=0 (Y), the base station terminates the CAP (S132).Otherwise (N), step 2 proceeds.

Step 5) (S160) The base station senses the channel until either a busysensing slot is detected within an additional defer duration T_(d) orall the slots of the additional defer duration T_(d) are detected to beidle.

Step 6) (S170) If the channel is sensed to be idle for all the slotdurations of the additional defer duration T_(d) (Y), step 4 proceeds.Otherwise (N), step 5 proceeds.

Table 10 shows that m_(p), a minimum contention window (CW), a maximumCW, a maximum channel occupancy time (MCOT), and an allowed CW size,which are applied to the CAP, vary depending on channel access priorityclasses.

TABLE 10 Channel Access Priority Class (p) m_(p) CWmin, _(p) CW max,_(p) T_(mcot,p) allowed CW_(p) sizes 1 1 3 7 2 ms {3,7} 2 1 7 15 3 ms{7,15} 3 3 15 63 8 or 10 ms {15,31,63} 4 7 15 1023 8 or 10 ms{15,31,63,127,255,511,1023}

Referring to Table 10, a contention window size (CWS), a maximum COTvalue, etc. for each CAPC may be defined. For example, T_(d) may beequal to T_(f) + m_(p) * T_(sl) (T_(d) = T_(f)+ m_(p) * T_(sl)).

The defer duration T_(d) is configured in the following order: durationT_(f) (16 us) + m_(p) consecutive sensing slot durations T_(sl) (9 us).T_(f) includes the sensing slot duration T_(sl) at the beginning of the16 us duration.

The following relationship is satisfied: CW_(min,p) <= CW_(p) <=CW_(max,p). CW_(p) may be configured by CW_(p) = CW_(mill,p) and updatedbefore step 1 based on HARQ-ACK feedback (e.g., the ratio of ACK orNACK) for a previous DL burst (e.g., PDSCH) (CW size update). Forexample, CW_(p) may be initialized to CW_(min,p) based on the HARQ-ACKfeedback for the previous DL burst. Alternatively, CW_(p) may beincreased to the next higher allowed value or maintained as it is.

(2) Type 2 Downlink (DL) CAP Method

In the type 2 DL CAP, the length of a time duration spanned by sensingslots sensed to be idle before transmission(s) may be determined. Thetype 2 DL CAP is classified into type 2A/2B/2C DL CAPs.

The type 2A DL CAP may be applied to the following transmissions. In thetype 2A DL CAP, the base station may perform transmission immediatelyafter the channel is sensed to be idle at least for a sensing durationT_(short_dl) = 25 us. Herein, T_(short_dl) includes the duration T_(f)(=16 us) and one sensing slot duration immediately after the durationT_(f), where the duration T_(f) includes a sensing slot at the beginningthereof.

-   Transmission(s) initiated by the base station including (i) a    discovery burst only or (ii) a discovery burst multiplexed with    non-unicast information, or-   Transmission(s) by the base station after a gap of 25 us from    transmission(s) by the UE within a shared channel occupancy.

The type 2B DL CAP is applicable to transmission(s) performed by thebase station after a gap of 16 us from transmission(s) by the UE withina shared channel occupancy time. In the type 2B DL CAP, the base stationmay perform transmission immediately after the channel is sensed to beidle for T_(f) = 16 us. T_(f) includes a sensing slot within 9 us fromthe end of the duration. The type 2C DL CAP is applicable totransmission(s) performed by the base station after a maximum of 16 usfrom transmission(s) by the UE within the shared channel occupancy time.In the type 2C DL CAP, the base station does not perform channel sensingbefore performing transmission.

Hereinafter, a method of transmitting an uplink signal through anunlicensed band will be described. For example, a method of transmittingan uplink signal through an unlicensed band may be applied to a methodof transmitting a sidelink signal through an unlicensed band.

The UE may perform type 1 or type 2 CAP for UL signal transmission in anunlicensed band. In general, the UE may perform the CAP (e.g., type 1 ortype 2) configured by the base station for UL signal transmission. Forexample, a UL grant scheduling PUSCH transmission (e.g., DCI formats 0_0and 0_1) may include CAP type indication information for the UE.

(1) Type 1 Uplink (UL) CAP Method

In the type 1 UL CAP, the length of a time duration spanned by sensingslots sensed to be idle before transmission(s) is random. The type 1 ULCAP may be applied to the following transmissions.

-   PUSCH/SRS transmission(s) scheduled and/or configured by the base    station-   PUCCH transmission(s) scheduled and/or configured by the base    station-   Transmission(s) related to a random access procedure (RAP)

FIG. 12 shows type 1 CAP operations performed by a UE to transmit anuplink signal, based on an embodiment of the present disclosure. Theembodiment of FIG. 12 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 12 , the UE may sense whether a channel is idle forsensing slot durations of a defer duration T_(d). Then, if a counter Nis zero, the UE may perform transmission (S234). In this case, the UEmay adjust the counter N by sensing the channel for additional sensingslot duration(s) according to the following steps:

Step 1) (S220) The UE sets N to N_(init) (N = N_(init)), where N_(init)is a random number uniformly distributed between 0 and CW_(p). Then,step 4 proceeds.

Step 2) (S240) If N>0 and the UE determines to decrease the counter, theUE sets N to N-1 (N = N-1).

Step 3) (S250) The UE senses the channel for the additional sensing slotduration. If the additional sensing slot duration is idle (Y), step 4proceeds. Otherwise (N), step 5 proceeds.

Step 4) (S230) If N=0 (Y), the UE terminates the CAP (S232). Otherwise(N), step 2 proceeds.

Step 5) (S260) The UE senses the channel until either a busy sensingslot is detected within an additional defer duration T_(d) or all theslots of the additional defer duration T_(d) are detected to be idle.

Step 6) (S270) If the channel is sensed to be idle for all the slotdurations of the additional defer duration T_(d) (Y), step 4 proceeds.Otherwise (N), step 5 proceeds.

Table 11 shows that m_(p), a minimum CW, a maximum CW, a maximum channeloccupancy time (MCOT), and an allowed CW size, which are applied to theCAP, vary depending on channel access priority classes.

TABLE 11 Channel Access Priority Class (p) m_(p) CW_(min,) _(p)CW_(max,) _(p) T_(ulmcot,p) allowed CW_(p) sizes 1 2 3 7 2 ms {3,7} 2 27 15 4 ms {7,15} 3 3 15 1023 6 or 10 ms {15,31,63,127,255,511,1023} 4 715 1023 6 or 10 ms {15,31,63,127,255,511,1023}

Referring to Table 11, a contention window size (CWS), a maximum COTvalue, etc. for each CAPC may be defined. For example, T_(d) may beequal to T_(f) + m_(p) * T_(sl) (T_(d) = T_(f)+ m_(p) * T_(sl))_(.)

The defer duration T_(d) is configured in the following order: durationT_(f) (16 us) + m_(p) consecutive sensing slot durations T_(sl) (9 us).T_(f) includes the sensing slot duration T_(sl) at the beginning of the16 us duration.

The following relationship is satisfied: CW_(min,p) <= CW_(p) <=CW_(max,p). CW_(p) may be configured by CW_(p) = CW_(min,p) and updatedbefore step 1 based on an explicit/implicit reception response for aprevious UL burst (e.g., PUSCH) (CW size update). For example, CW_(p)may be initialized to CW_(min,p) based on the explicit/implicitreception response for the previous UL burst. Alternatively, CW_(p) maybe increased to the next higher allowed value or maintained as it is.

(2) Type 2 Uplink (UL) CAP Method

In the type 2 UL CAP, the length of a time duration spanned by sensingslots sensed to be idle before transmission(s) may be determined. Thetype 2 UL CAP is classified into type 2A/2B/2C UL CAPs. In the type 2AUL CAP, the UE may perform transmission immediately after the channel issensed to be idle at least for a sensing duration T_(short_dl) = 25 us.Herein, T_(short_dl) includes the duration T_(f) (= 16 us) and onesensing slot duration immediately after the duration T_(f). In the type2A UL CAP, T_(f) includes a sensing slot at the beginning thereof. Inthe type 2B UL CAP, the UE may perform transmission immediately afterthe channel is sensed to be idle for the sensing duration T_(f) = 16 us.In the type 2B UL CAP, T_(f) includes a sensing slot within 9 us fromthe end of the duration. In the type 2C UL CAP, the UE does not performchannel sensing before performing transmission.

For example, according to the type 1 LBT-based NR-U operation, the UEhaving uplink data to be transmitted may select a CAPC mapped to 5QI ofdata, and the UE may perform the NR-U operation by applying parametersof the corresponding CACP (e.g., minimum contention window size, maximumcontention window size, m_(p), etc.). For example, the UE may select abackoff counter (BC) after selecting a random value between the minimumCW and the maximum CW mapped to the CAPC. In this case, for example, theBC may be a positive integer less than or equal to the random value. TheUE sensing a channel decreases the BC by 1 if the channel is idle. Ifthe BC becomes zero and the UE detects that the channel is idle for thetime T_(d) (T_(d) = T_(f) + m_(p) * T_(sl)), the UE may attempt totransmit data by occupying the channel. For example, T_(sl) (= 9 usec)is a basic sensing unit or sensing slots, and may include a measurementduration for at least 4 usec. For example, the front 9 usec of T_(f) (=16 usec) may be configured to be T_(sl).

For example, according to the type 2 LBT-based NR-U operation, the UEmay transmit data by performing the type 2 LBT (e.g., type 2A LBT, type2B LBT, or type 2C LBT) within COT.

For example, the type 2A (also referred to as Cat-2 LBT (one shot LBT)or one-shot LBT) may be 25 usec one-shot LBT. In this case, transmissionmay start immediately after idle sensing for at least a 25 usec gap. Thetype 2A may be used to initiate transmission of SSB and non-unicast DLinformation. That is, the UE may sense a channel for 25 usec within COT,and if the channel is idle, the UE may attempt to transmit data byoccupying the channel.

For example, the type 2B may be 16 usec one-shot LBT. In this case,transmission may start immediately after idle sensing for a 16 usec gap.That is, the UE may sense a channel for 16 usec within COT, and if thechannel is idle, the UE may attempt to transmit data by occupying thechannel.

For example, in the case of the type 2C (also referred to as Cat-1 LBTor No LBT), LBT may not be performed. In this case, transmission maystart immediately after a gap of up to 16 usec and a channel may not besensed before the transmission. The duration of the transmission may beup to 584 usec. The UE may attempt transmission after 16 usec withoutsensing, and the UE may perform transmission for up to 584 usec.

In a sidelink unlicensed band, the UE may perform a channel accessoperation based on Listen Before Talk (LBT). Before the UE accesses achannel in an unlicensed band, the UE should check whether the channelto be accessed is idle (e.g., a state in which UEs do not occupy thechannel, a state in which UEs can access the corresponding channel andtransmit data) or busy (e.g., a state in which the channel is occupiedand data transmission/reception is performed on the correspondingchannel, and the UE attempting to access the channel cannot transmitdata while the channel is busy). That is, the operation in which the UEchecks whether the channel is idle or busy may be referred to as ClearChannel Assessment (CCA), and the UE may check whether the channel isidle or busy for the CCA duration.

FIG. 13 shows a channel access procedure, based on an embodiment of thepresent disclosure. Specifically, (a) of FIG. 13 shows an example of adynamic channel access procedure (load based equipment, LBE), and (b) ofFIG. 13 shows an example of a semi-static channel access procedure(frame based equipment, FBE). The embodiment of FIG. 13 may be combinedwith various embodiments of the present disclosure.

Referring to (a) of FIG. 13 , if a channel is idle, the UE may performcontention with other UEs on an unlicensed band to immediately occupythe channel. In addition, if the UE occupies the channel, the UE maytransmit data.

Referring to (b) of FIG. 13 , the UE may perform contention with otherUEs on an unlicensed band at the last time within a synchronized frameboundary (or a fixed frame period (FFP)) (e.g., certain time before thestart of the next FFP (or starting time)). In addition, if the UEoccupies a channel within a fixed frame period (FFP), the UE maytransmit data. The data transmission should complete before the next FFPbegins.

Meanwhile, the UE attempting SL communication based on a frame in anunlicensed band may fail to occupy a channel within the frame due tocommunication of other UEs. If the UE continuously attempts to occupythe channel despite the failure of the UE to occupy the channel based onframe-related configuration information, battery consumption mayincrease due to unnecessary sensing of the UE, and quality of service(QoS) requirements of a packet to be transmitted may not be satisfied.

Based on various embodiments of the present disclosure, a method of FBEoperations of a UE, a method of UE operations for an FBE configurationfailure operation, and an apparatus supporting the same are proposed.

FIG. 14 shows a procedure for a UE to perform channel occupation inunits of a frame in an unlicensed band, based on an embodiment of thepresent disclosure. The embodiment of FIG. 14 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 14 , in step S1410, the base station may provide theUE with FBE configuration information to be used by the UE. For example,the FBE configuration information may include FFP information, an FFPstart offset, etc. For example, if the UE A and the UE B establish aunicast configuration and perform SL data transmission/receptionoperations, the base station may provide the UE A or the UE B with FBEconfiguration information to be used by the UE A or the UE B.

For example, the base station may provide the UE A with FBEconfiguration information to be used by the UE A to transmit data to theUE B.

In step S1420, the UE A which has received the FBE configurationinformation may perform contention within an FFP based on the FFPinformation. In this case, if the UE A wins the contention and occupiesa channel, the UE A may transmit data to the UE B on the occupiedchannel within the FFP. In addition, the UE A which has received the FBEconfiguration information may perform data transmission by performingthe type 2 LBT within the FFP. That is, the UE A may not perform LBTbased on random backoff within the FFP, and the UE A may transmit databy performing short LBT. Herein, for example, the short LBT may be thetype 2 LBT, and the UE A may sense the channel for a short time andimmediately transmit data when the channel is idle.

In step S1430, if the UE A performs the type 2 LBT within the configuredFFP, but the channel continues to be busy and data transmission fails,in step S1440, the UE A may inform the base station, which provided FBEconfiguration information, of an FBE configuration failure. For example,if the number of failed channel occupancy reaches a threshold, the UE Amay inform the base station, which provided FBE configurationinformation, of an FBE configuration failure. For example, informationrelated to the FBE configuration failure may be transmitted through adedicated RRC message. For example, information related to the FBEconfiguration failure may be transmitted through a MAC CE. For example,information related to the FBE configuration failure may be transmittedthrough a PUCCH. If the base station receives feedback regarding the FBEconfiguration failure from the UE A which receives and uses the FBEconfiguration information, the base station may reconfigure the FBEconfiguration information and provide it to the UE A. For example, thereconfigured FBE configuration information may be transmitted through adedicated RRC message. For example, the reconfigured FBE configurationinformation may be transmitted through a MAC CE. For example, thereconfigured FBE configuration information may be transmitted through aPDCCH. Alternatively, if the base station receives feedback regardingthe FBE configuration failure from the UE A which receives and uses theFBE configuration information, the base station may instruct the UE A toswitch to the LBE and perform the SL-U operation. For example,information notifying to perform the LBE-based SL-U operation may betransmitted through a dedicated RRC message. For example, informationnotifying to perform the LBE-based SL-U operation may be transmittedthrough a MAC CE. For example, information notifying to perform theLBE-based SL-U operation may be transmitted through a PDCCH.

FIG. 15 shows a method for a UE to perform channel occupation in unitsof a frame in an unlicensed band, based on an embodiment of the presentdisclosure. The embodiment of FIG. 15 may be combined with variousembodiments of the present disclosure.

Referring to FIG. 15 , in order to determine whether transmission ispossible within an FFP, the UE may perform sensing (e.g., LBT) beforethe start of the FFP. If the UE determines that transmission is possiblewithin the FFP based on a result of the sensing, the UE may performtransmission by occupying a channel within the FFP. If the UE determinesthat transmission is impossible within the FFP based on the result ofthe sensing, the UE may perform sensing before the start of the nextFFP. For example, if the number of failures to occupy the channelreaches a threshold (e.g., if the number of failures to occupy thechannel is greater than or equal to the threshold), the UE may transmitinformation regarding an FBE configuration failure. For example, thethreshold may be configured differently or independently for the UEaccording to various embodiments of the present disclosure.

FIG. 16 shows a procedure for a UE to perform channel occupation inunits of a frame in an unlicensed band, based on an embodiment of thepresent disclosure. The embodiment of FIG. 16 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 16 , in step S1610, the base station may provide FBEconfiguration information to be used by the UE B to transmit data to theUE A with the UE A. For example, the FBE configuration information mayinclude FFP information, an FFP start offset, etc.

In step S1620, the UE A which has received the FBE configurationinformation may forward the FBE configuration information to the UE B.For example, the FBE configuration information may be forwarded throughSCI. For example, the FBE configuration information may be forwardedthrough a MAC CE. For example, the FBE configuration information may beforwarded through a PC5 RRC message.

In step S1630, the UE B which has received the FBE configurationinformation may perform contention within an FFP based on the FFPinformation. In this case, if the UE B wins the contention and occupiesa channel, the UE B may transmit data to the UE A on the occupiedchannel within the FFP. In addition, the UE B which has received the FBEconfiguration information may perform data transmission by performingthe type 2 LBT within the FFP. That is, the UE B may not perform LBTbased on random backoff within the FFP, and the UE B may transmit databy performing short LBT. Herein, for example, the short LBT may be thetype 2 LBT, and the UE B may sense the channel for a short time andimmediately transmit data when the channel is idle.

In step S1640, if the UE B performs the type 2 LBT within the configuredFFP, but the channel continues to be busy and data transmission fails,in step S1650, the UE B may inform the UE A, which provided FBEconfiguration information, of an FBE configuration failure. For example,information related to the FBE configuration failure may be transmittedthrough a PC5 RRC message. For example, information related to the FBEconfiguration failure may be transmitted through a MAC CE. For example,information related to the FBE configuration failure may be transmittedthrough SCI.

In step S 1660, if the UE A receives feedback or a message regarding theFBE configuration failure from the UE B, the UE A may report the FBEconfiguration failure to the base station. For example, the FBEconfiguration failure may be reported through a dedicated RRC message.For example, the FBE configuration failure may be reported through a MACCE. For example, the FBE configuration failure may be reported through aPUCCH. When the UE A reports the FBE configuration failure to the basestation, the UE A may also report an L2 destination ID of the UE whichuses the FBE configuration information.

For example, if the base station receives the feedback regarding the FBEconfiguration failure from the UE A, the base station may reconfigurethe FBE configuration information and provide it to the UE A. Forexample, the reconfigured FBE configuration information may betransmitted through a dedicated RRC message. For example, thereconfigured FBE configuration information may be transmitted through aMAC CE. For example, the reconfigured FBE configuration information maybe transmitted through a PDCCH. When the base station reconfigures theFBE configuration information to the UE A and transmits it to the UE A,the base station may also transmit an L2 destination ID of the UE whichuses the reconfigured FBE configuration information. Alternatively, ifthe base station receives the feedback regarding the FBE configurationfailure (e.g., FBE operation failure of the UE B) from the UE A, thebase station may instruct the UE A such that the UE B switches to theLBE and performs the SL-U operation. For example, information notifyingto perform the LBE-based SL-U operation may be transmitted through adedicated RRC message. For example, information notifying to perform theLBE-based SL-U operation may be transmitted through a MAC CE. Forexample, information notifying to perform the LBE-based SL-U operationmay be transmitted through a PDCCH. If the UE A receives FBEreconfiguration information or LBE switching operation indicationinformation from the base station, the UE A may transmit the informationto the UE B. Through this, the UE B may perform SL-U data transmissionoperation by using the FBE configuration information reconfigured by thebase station, or the UE B may switch to the LBE and perform the SL-Udata transmission operation. In addition, based on an embodiment of thepresent disclosure, if the UE B receives FBE configuration informationfrom the UE A or a serving base station of the UE A, the UE B may reportthe received FBE configuration information to its own serving basestation (the serving base station of the UE B). Herein, for example, theFBE configuration information may be reported through sidelink UEinformation. For example, the FBE configuration information may bereported through UE assistance information. For example, the FBEconfiguration information may be reported through other RRC messages.Through this, the base station may refer to the FBE configurationinformation for alignment for various operations of the UE B (e.g.,alignment between an FBE configuration of the UE B and a COTconfiguration of the base station/other UEs or alignment between an FBEconfiguration of the UE B and a Uu/SL DRX configuration of the UE B).

For example, if the UE fails to transmit SL data by using FBEconfiguration information, the UE may determine an FBE configurationfailure. In this case, if the UE transmits a report regarding thefailure to the base station or other UEs which has transmitted the FBEconfiguration information, the UE may perform SL data transmission bycontinuing to use the existing failed FBE configuration informationuntil receiving a reconfigured FBE (or receiving an LBE switchingindication).

For example, information on whether to perform an FBE operation or anLBE operation for SL-U data transmission between UEs may be exchangedwith each other. For example, the information may be exchanged throughSCI. For example, the information may be exchanged through a MAC CE. Forexample, the information may be exchanged through a PC5 RRC message.

For example, the report regarding the FBE configuration failure reportedby the UE may be transferred by being included in a dedicated RRCmessage, a PC5 RRC message, a Uu/SL MAC CE, SCI, a PUCCH, etc. as acause (e.g., FBE configuration failure).

For example, whether or not the (some) proposed method/rule of thepresent disclosure is applied and/or related parameter(s) (e.g.,threshold value(s)) may be configured (differently or independently) foreach SL-Channel Access Priority Class (CAPC). For example, whether ornot the (some) proposed method/rule of the present disclosure is appliedand/or related parameter(s) (e.g., threshold value(s)) may be configured(differently or independently) for each SL-LBT type (e.g., Type 1 LBT,Type 2A LBT, Type 2B LBT, Type 2C LBT). For example, whether or not the(some) proposed method/rule of the present disclosure is applied and/orrelated parameter(s) (e.g., threshold value(s)) may be configuredspecifically (or differently or independently) depending on whether ornot Frame Based LBT is applied. For example, whether or not the (some)proposed method/rule of the present disclosure is applied and/or relatedparameter(s) (e.g., threshold value(s)) may be configured specifically(or differently or independently) depending on whether or not Load BasedLBT is applied.

For example, whether or not the (some) proposed method/rule of thepresent disclosure is applied and/or related parameter(s) (e.g.,threshold value(s)) may be configured (differently or independently) foreach resource pool. For example, whether or not the (some) proposedmethod/rule of the present disclosure is applied and/or relatedparameter(s) (e.g., threshold value(s)) may be configured (differentlyor independently) for each congestion level. For example, whether or notthe (some) proposed method/rule of the present disclosure is appliedand/or related parameter(s) (e.g., threshold value(s)) may be configured(differently or independently) for each service priority. For example,whether or not the (some) proposed method/rule of the present disclosureis applied and/or related parameter(s) (e.g., threshold value(s)) may beconfigured (differently or independently) for each service type. Forexample, whether or not the (some) proposed method/rule of the presentdisclosure is applied and/or related parameter(s) (e.g., thresholdvalue(s)) may be configured (differently or independently) for each QoSrequirement (e.g., latency, reliability). For example, whether or notthe (some) proposed method/rule of the present disclosure is appliedand/or related parameter(s) (e.g., threshold value(s)) may be configured(differently or independently) for each PQI (5G QoS identifier (5QI) forPC5). For example, whether or not the (some) proposed method/rule of thepresent disclosure is applied and/or related parameter(s) (e.g.,threshold value(s)) may be configured (differently or independently) foreach traffic type (e.g., periodic generation or aperiodic generation).For example, whether or not the (some) proposed method/rule of thepresent disclosure is applied and/or related parameter(s) (e.g.,threshold value(s)) may be configured (differently or independently) foreach SL transmission resource allocation mode (e.g., mode 1 or mode 2).For example, whether or not the (some) proposed method/rule of thepresent disclosure is applied and/or related parameter(s) (e.g.,threshold value(s)) may be configured (differently or independently) foreach Tx profile (e.g., a Tx profile indicating that a service supportssidelink DRX operation or a Tx profile indicating that a service doesnot need to support sidelink DRX operation).

For example, whether or not the proposed rule of the present disclosureis applied and/or related parameter configuration value(s) may beconfigured specifically (or differently or independently) depending onwhether a PUCCH configuration is supported (e.g., in case that a PUCCHresource is configured or in case that a PUCCH resource is notconfigured). For example, whether or not the proposed rule of thepresent disclosure is applied and/or related parameter configurationvalue(s) may be configured (differently or independently) for eachresource pool (e.g., a resource pool with a PSFCH or a resource poolwithout a PSFCH). For example, whether or not the proposed rule of thepresent disclosure is applied and/or related parameter configurationvalue(s) may be configured (differently or independently) for eachsidelink logical channel/logical channel group (or Uu logical channel orUu logical channel group).

For example, whether or not the proposed rule of the present disclosureis applied and/or related parameter configuration value(s) may beconfigured (differently or independently) for each resource pool. Forexample, whether or not the proposed rule of the present disclosure isapplied and/or related parameter configuration value(s) may beconfigured (differently or independently) for each service/packet type.For example, whether or not the proposed rule of the present disclosureis applied and/or related parameter configuration value(s) may beconfigured (differently or independently) for each service/packetpriority. For example, whether or not the proposed rule of the presentdisclosure is applied and/or related parameter configuration value(s)may be configured (differently or independently) for each QoSrequirement (e.g., URLLC/EMBB traffic, reliability, latency). Forexample, whether or not the proposed rule of the present disclosure isapplied and/or related parameter configuration value(s) may beconfigured (differently or independently) for each PQI. For example,whether or not the proposed rule of the present disclosure is appliedand/or related parameter configuration value(s) may be configured(differently or independently) for each PFI. For example, whether or notthe proposed rule of the present disclosure is applied and/or relatedparameter configuration value(s) may be configured (differently orindependently) for each cast type (e.g., unicast, groupcast, broadcast).For example, whether or not the proposed rule of the present disclosureis applied and/or related parameter configuration value(s) may beconfigured (differently or independently) for each (resource pool)congestion level (e.g., CBR). For example, whether or not the proposedrule of the present disclosure is applied and/or related parameterconfiguration value(s) may be configured (differently or independently)for each SL HARQ feedback option (e.g., NACK-only feedback, ACK/NACKfeedback). For example, whether or not the proposed rule of the presentdisclosure is applied and/or related parameter configuration value(s)may be configured specifically (or differently or independently) forHARQ Feedback Enabled MAC PDU transmission. For example, whether or notthe proposed rule of the present disclosure is applied and/or relatedparameter configuration value(s) may be configured specifically (ordifferently or independently) for HARQ Feedback Disabled MAC PDUtransmission. For example, whether or not the proposed rule of thepresent disclosure is applied and/or related parameter configurationvalue(s) may be configured specifically (or differently orindependently) according to whether a PUCCH-based SL HARQ feedbackreporting operation is configured or not. For example, whether or notthe proposed rule of the present disclosure is applied and/or relatedparameter configuration value(s) may be configured specifically (ordifferently or independently) for pre-emption or depending on whether ornot pre-emption-based resource reselection is performed. For example,whether or not the proposed rule of the present disclosure is appliedand/or related parameter configuration value(s) may be configuredspecifically (or differently or independently) for re-evaluation ordepending on whether or not re-evaluation-based resource reselection isperformed. For example, whether or not the proposed rule of the presentdisclosure is applied and/or related parameter configuration value(s)may be configured (differently or independently) for each (L2 or L1)(source and/or destination) identifier. For example, whether or not theproposed rule of the present disclosure is applied and/or relatedparameter configuration value(s) may be configured (differently orindependently) for each (L2 or L1) (a combination of source ID anddestination ID) identifier. For example, whether or not the proposedrule of the present disclosure is applied and/or related parameterconfiguration value(s) may be configured (differently or independently)for each (L2 or L1) (a combination of a pair of source ID anddestination ID and a cast type) identifier. For example, whether or notthe proposed rule of the present disclosure is applied and/or relatedparameter configuration value(s) may be configured (differently orindependently) for each direction of a pair of source layer ID anddestination layer ID. For example, whether or not the proposed rule ofthe present disclosure is applied and/or related parameter configurationvalue(s) may be configured (differently or independently) for each PC5RRC connection/link. For example, whether or not the proposed rule ofthe present disclosure is applied and/or related parameter configurationvalue(s) may be configured specifically (or differently orindependently) depending on whether or not SL DRX is performed. Forexample, whether or not the proposed rule of the present disclosure isapplied and/or related parameter configuration value(s) may beconfigured specifically (or differently or independently) depending onwhether or not SL DRX is supported. For example, whether or not theproposed rule of the present disclosure is applied and/or relatedparameter configuration value(s) may be configured (differently orindependently) for each SL mode type (e.g., resource allocation mode 1or resource allocation mode 2). For example, whether or not the proposedrule of the present disclosure is applied and/or related parameterconfiguration value(s) may be configured specifically (or differently orindependently) for the case of performing (a)periodic resourcereservation. For example, whether or not the proposed rule of thepresent disclosure is applied and/or related parameter configurationvalue(s) may be configured specifically (or differently orindependently) for each Tx profile (e.g., a Tx profile indicating that aservice supports sidelink DRX operation or a Tx profile indicating thata service does not need to support sidelink DRX operation).

The proposal and whether or not the proposal rule of the presentdisclosure is applied (and/or related parameter configuration value(s))may also be applied to a mmWave SL operation.

Based on various embodiments of the present disclosure, if a UEattempting SL communication based on a frame in an unlicensed band failsto occupy a channel within the frame due to communication of other UEs,the UE may transmit failure information. In this case, the UE mayattempt channel occupation based on frame-related reconfigurationinformation or LBE indication information. Accordingly, it is possibleto prevent a problem in which battery consumption increases due tounnecessary sensing of the UE or a problem in which quality of service(QoS) requirements of a packet to be transmitted are not satisfied.

FIG. 17 shows a method for performing wireless communication by a firstdevice, based on an embodiment of the present disclosure. The embodimentof FIG. 17 may be combined with various embodiments of the presentdisclosure.

Referring to FIG. 17 , in step S1710, the first device may obtainconfiguration information including at least one of information relatedto a first fixed frame period (FFP) or information related to a firstFFP offset. In step S1720, the first device may determine a plurality ofFFPs based on the configuration information. In step S1730, the firstdevice may perform sensing related to the plurality of FFPs. In stepS1740, the first device may determine whether a channel is idle withinthe plurality of FFPs based on the sensing related to the plurality ofFFPs. In step S1750, the first device may transmit information relatedto a failure of the configuration information, based on a number ofnon-idle channels reaching a threshold.

For example, the configuration information may be received from a basestation, and the information related to the failure of the configurationinformation may be transmitted to the base station. Additionally, forexample, the first device may receive, from the base station,reconfiguration information including at least one of informationrelated to a second FFP or information related to a second FFP offset,in response to the information related to the failure of theconfiguration information. Additionally, for example, the first devicemay receive, from the base station, information for load based equipment(LBE)-based unlicensed band communication, in response to theinformation related to the failure of the configuration information. Forexample, based on the information for the LBE-based unlicensed bandcommunication, a sensing operation in units of a fixed frame based onthe configuration information may be stopped.

For example, the configuration information may be received from a seconddevice, and the information related to the failure of the configurationinformation may be transmitted to the second device. Additionally, forexample, the first device may receive, from the second device,reconfiguration information including at least one of informationrelated to a second FFP or information related to a second FFP offset,in response to the information related to the failure of theconfiguration information. Additionally, for example, the first devicemay transmit the reconfiguration information to a serving base stationof the first device.

For example, the first device may perform sidelink (SL) communication inan unlicensed band based on the configuration information, aftertransmitting the information related to the failure of the configurationinformation and before receiving reconfiguration information orinformation for load based equipment (LBE)-based unlicensed bandcommunication.

Additionally, for example, the first device may transmit, to at leastone device, information representing that FFP-based unlicensed bandcommunication is performed or information representing that load basedequipment (LBE)-based unlicensed band communication is performed.

For example, the sensing related to the plurality of FFPs may beperformed during each time duration before a start of each of theplurality of FFPs.

For example, the threshold may be configured for the first device basedon a channel access priority class (CAPC).

For example, the threshold may be configured for the first device foreach resource pool.

For example, the configuration information may be determined by thefirst device.

The proposed method can be applied to the device(s) based on variousembodiments of the present disclosure. First, the processor 102 of thefirst device 100 may obtain configuration information including at leastone of information related to a first fixed frame period (FFP) orinformation related to a first FFP offset. In addition, the processor102 of the first device 100 may determine a plurality of FFPs based onthe configuration information. In addition, the processor 102 of thefirst device 100 may perform sensing related to the plurality of FFPs.In addition, the processor 102 of the first device 100 may determinewhether a channel is idle within the plurality of FFPs based on thesensing related to the plurality of FFPs. In addition, the processor 102of the first device 100 may control the transceiver 106 to transmitinformation related to a failure of the configuration information, basedon a number of non-idle channels reaching a threshold.

Based on an embodiment of the present disclosure, a first device adaptedto perform wireless communication may be provided. For example, thefirst device may comprise: at least one transceiver; at least oneprocessor; and at least one memory connected to the at least oneprocessor and storing instructions. For example, the instructions, basedon being executed by the at least one processor, may perform operationscomprising: obtaining configuration information including at least oneof information related to a first fixed frame period (FFP) orinformation related to a first FFP offset; determining a plurality ofFFPs based on the configuration information; performing sensing relatedto the plurality of FFPs; determining whether a channel is idle withinthe plurality of FFPs based on the sensing related to the plurality ofFFPs; and transmitting information related to a failure of theconfiguration information, based on a number of non-idle channelsreaching a threshold.

Based on an embodiment of the present disclosure, a processing deviceadapted to control a first device may be provided. For example, theprocessing device may comprise: at least one processor; and at least onememory connected to the at least one processor and storing instructions.For example, the instructions, based on being executed by the at leastone processor, may perform operations comprising: obtainingconfiguration information including at least one of information relatedto a first fixed frame period (FFP) or information related to a firstFFP offset; determining a plurality of FFPs based on the configurationinformation; performing sensing related to the plurality of FFPs;determining whether a channel is idle within the plurality of FFPs basedon the sensing related to the plurality of FFPs; and transmittinginformation related to a failure of the configuration information, basedon a number of non-idle channels reaching a threshold.

Based on an embodiment of the present disclosure, a non-transitorycomputer readable storage medium storing instructions may be provided.For example, the instructions, when executed, may cause a first deviceto: obtain configuration information including at least one ofinformation related to a first fixed frame period (FFP) or informationrelated to a first FFP offset; determine a plurality of FFPs based onthe configuration information; perform sensing related to the pluralityof FFPs; determine whether a channel is idle within the plurality ofFFPs based on the sensing related to the plurality of FFPs; and transmitinformation related to a failure of the configuration information, basedon a number of non-idle channels reaching a threshold.

FIG. 18 shows a method for performing wireless communication by a seconddevice, based on an embodiment of the present disclosure. The embodimentof FIG. 18 may be combined with various embodiments of the presentdisclosure.

Referring to FIG. 18 , in step S1810, the second device may receive,from a base station, configuration information including at least one ofinformation related to a fixed frame period (FFP) or information relatedto an FFP offset. In step S1820, the second device may transmit, to afirst device, the configuration information. In step S1830, the seconddevice may receive, from the first device, information related to afailure of the configuration information based on a number of non-idlechannels reaching a threshold. In step S1840, the second device maytransmit, to the base station, the information related to the failure ofthe configuration information.

The proposed method can be applied to the device(s) based on variousembodiments of the present disclosure. First, the processor 202 of thesecond device 200 may control the transceiver 206 to receive, from abase station, configuration information including at least one ofinformation related to a fixed frame period (FFP) or information relatedto an FFP offset. In addition, the processor 202 of the second device200 may control the transceiver 206 to transmit, to a first device, theconfiguration information. In addition, the processor 202 of the seconddevice 200 may control the transceiver 206 to receive, from the firstdevice, information related to a failure of the configurationinformation based on a number of non-idle channels reaching a threshold.In addition, the processor 202 of the second device 200 may control thetransceiver 206 to transmit, to the base station, the informationrelated to the failure of the configuration information.

Based on an embodiment of the present disclosure, a second deviceadapted to perform wireless communication may be provided. For example,the second device may comprise: at least one transceiver; at least oneprocessor; and at least one memory connected to the at least oneprocessor and storing instructions. For example, the instructions, basedon being executed by the at least one processor, may perform operationscomprising: receiving, from a base station, configuration informationincluding at least one of information related to a fixed frame period(FFP) or information related to an FFP offset; transmitting, to a firstdevice, the configuration information; receiving, from the first device,information related to a failure of the configuration information basedon a number of non-idle channels reaching a threshold; and transmitting,to the base station, the information related to the failure of theconfiguration information.

Based on an embodiment of the present disclosure, a processing deviceadapted to control a second device may be provided. For example, theprocessing device may comprise: at least one processor; and at least onememory connected to the at least one processor and storing instructions.For example, the instructions, based on being executed by the at leastone processor, may perform operations comprising: receiving, from a basestation, configuration information including at least one of informationrelated to a fixed frame period (FFP) or information related to an FFPoffset; transmitting, to a first device, the configuration information;receiving, from the first device, information related to a failure ofthe configuration information based on a number of non-idle channelsreaching a threshold; and transmitting, to the base station, theinformation related to the failure of the configuration information.

Based on an embodiment of the present disclosure, a non-transitorycomputer readable storage medium storing instructions may be provided.For example, the instructions, when executed, may cause a second deviceto: receive, from a base station, configuration information including atleast one of information related to a fixed frame period (FFP) orinformation related to an FFP offset; transmit, to a first device, theconfiguration information; receive, from the first device, informationrelated to a failure of the configuration information based on a numberof non-idle channels reaching a threshold; and transmit, to the basestation, the information related to the failure of the configurationinformation.

Various embodiments of the present disclosure may be combined with eachother.

Hereinafter, device(s) to which various embodiments of the presentdisclosure can be applied will be described.

The various descriptions, functions, procedures, proposals, methods,and/or operational flowcharts of the present disclosure described inthis document may be applied to, without being limited to, a variety offields requiring wireless communication/connection (e.g., 5G) betweendevices.

Hereinafter, a description will be given in more detail with referenceto the drawings. In the following drawings/description, the samereference symbols may denote the same or corresponding hardware blocks,software blocks, or functional blocks unless described otherwise.

FIG. 19 shows a communication system 1, based on an embodiment of thepresent disclosure. The embodiment of FIG. 19 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 19 , a communication system 1 to which variousembodiments of the present disclosure are applied includes wirelessdevices, Base Stations (BSs), and a network. Herein, the wirelessdevices represent devices performing communication using Radio AccessTechnology (RAT) (e.g., 5G New RAT (NR)) or Long-Term Evolution (LTE))and may be referred to as communication/radio/5G devices. The wirelessdevices may include, without being limited to, a robot 100 a, vehicles100 b-1 and 100 b-2, an eXtended Reality (XR) device 100 c, a hand-helddevice 100 d, a home appliance 100 e, an Internet of Things (IoT) device100 f, and an Artificial Intelligence (AI) device/server 400. Forexample, the vehicles may include a vehicle having a wirelesscommunication function, an autonomous vehicle, and a vehicle capable ofperforming communication between vehicles. Herein, the vehicles mayinclude an Unmanned Aerial Vehicle (UAV) (e.g., a drone). The XR devicemay include an Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality(MR) device and may be implemented in the form of a Head-Mounted Device(HMD), a Head-Up Display (HUD) mounted in a vehicle, a television, asmartphone, a computer, a wearable device, a home appliance device, adigital signage, a vehicle, a robot, etc. The hand-held device mayinclude a smartphone, a smartpad, a wearable device (e.g., a smartwatchor a smartglasses), and a computer (e.g., a notebook). The homeappliance may include a TV, a refrigerator, and a washing machine. TheIoT device may include a sensor and a smartmeter. For example, the BSsand the network may be implemented as wireless devices and a specificwireless device 200 a may operate as a BS/network node with respect toother wireless devices.

Here, wireless communication technology implemented in wireless devices100 a to 100 f of the present disclosure may include Narrowband Internetof Things for low-power communication in addition to LTE, NR, and 6G. Inthis case, for example, NB-IoT technology may be an example of Low PowerWide Area Network (LPWAN) technology and may be implemented as standardssuch as LTE Cat NB1, and/or LTE Cat NB2, and is not limited to the namedescribed above. Additionally or alternatively, the wirelesscommunication technology implemented in the wireless devices 100 a to100 f of the present disclosure may perform communication based on LTE-Mtechnology. In this case, as an example, the LTE-M technology may be anexample of the LPWAN and may be called by various names includingenhanced Machine Type Communication (eMTC), and the like. For example,the LTE-M technology may be implemented as at least any one of variousstandards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTEnon-Bandwidth Limited (non-BL), 5) LTE-MTC, 6) LTE Machine TypeCommunication, and/or 7) LTE M, and is not limited to the name describedabove. Additionally or alternatively, the wireless communicationtechnology implemented in the wireless devices 100 a to 100 f of thepresent disclosure may include at least one of Bluetooth, Low Power WideArea Network (LPWAN), and ZigBee considering the low-powercommunication, and is not limited to the name described above. As anexample, the ZigBee technology may generate personal area networks (PAN)related to small/low-power digital communication based on variousstandards including IEEE 802.15.4, and the like, and may be called byvarious names.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without passing through theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g. Vehicle-to-Vehicle(V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, or 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200, or BS200/BS 200. Herein, the wireless communication/connections may beestablished through various RATs (e.g., 5G NR) such as uplink/downlinkcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter BS communication (e.g. relay, Integrated AccessBackhaul (IAB)). The wireless devices and the BSs/the wireless devicesmay transmit/receive radio signals to/from each other through thewireless communication/connections 150 a and 150 b. For example, thewireless communication/connections 150 a and 150 b may transmit/receivesignals through various physical channels. To this end, at least a partof various configuration information configuring processes, varioussignal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the present disclosure.

FIG. 20 shows wireless devices, based on an embodiment of the presentdisclosure. The embodiment of FIG. 20 may be combined with variousembodiments of the present disclosure.

Referring to FIG. 20 , a first wireless device 100 and a second wirelessdevice 200 may transmit radio signals through a variety of RATs (e.g.,LTE and NR). Herein, {the first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100 x andthe BS 200} and/or {the wireless device 100 x and the wireless device100x} of FIG. 19 .

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 102 may process informationwithin the memory(s) 104 to generate first information/signals and thentransmit radio signals including the first information/signals throughthe transceiver(s) 106. The processor(s) 102 may receive radio signalsincluding second information/signals through the transceiver 106 andthen store information obtained by processing the secondinformation/signals in the memory(s) 104. The memory(s) 104 may beconnected to the processor(s) 102 and may store a variety of informationrelated to operations of the processor(s) 102. For example, thememory(s) 104 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 102or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 102 and the memory(s) 104 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 106 may be connected to the processor(s) 102 andtransmit and/or receive radio signals through one or more antennas 108.Each of the transceiver(s) 106 may include a transmitter and/or areceiver. The transceiver(s) 106 may be interchangeably used with RadioFrequency (RF) unit(s). In the present disclosure, the wireless devicemay represent a communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process informationwithin the memory(s) 204 to generate third information/signals and thentransmit radio signals including the third information/signals throughthe transceiver(s) 206. The processor(s) 202 may receive radio signalsincluding fourth information/signals through the transceiver(s) 106 andthen store information obtained by processing the fourthinformation/signals in the memory(s) 204. The memory(s) 204 may beconnected to the processor(s) 202 and may store a variety of informationrelated to operations of the processor(s) 202. For example, thememory(s) 204 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 202 and the memory(s) 204 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 206 may be connected to the processor(s) 202 andtransmit and/or receive radio signals through one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the present disclosure, the wireless device may represent acommunication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more Service Data Unit(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Theone or more processors 102 and 202 may generate messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document and provide thegenerated signals to the one or more transceivers 106 and 206. The oneor more processors 102 and 202 may receive the signals (e.g., basebandsignals) from the one or more transceivers 106 and 206 and acquire thePDUs, SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be implemented using firmware or software and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or stored in the one or more memories 104 and 204 so as tobe driven by the one or more processors 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by Read-OnlyMemories (ROMs), Random Access Memories (RAMs), Electrically ErasableProgrammable Read-Only Memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, from one or moreother devices. For example, the one or more transceivers 106 and 206 maybe connected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, through the one ormore antennas 108 and 208. In this document, the one or more antennasmay be a plurality of physical antennas or a plurality of logicalantennas (e.g., antenna ports). The one or more transceivers 106 and 206may convert received radio signals/channels etc. from RF band signalsinto baseband signals in order to process received user data, controlinformation, radio signals/channels, etc. using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, radio signals/channels, etc.processed using the one or more processors 102 and 202 from the baseband signals into the RF band signals. To this end, the one or moretransceivers 106 and 206 may include (analog) oscillators and/orfilters.

FIG. 21 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure. The embodiment of FIG. 21may be combined with various embodiments of the present disclosure.

Referring to FIG. 21 , a signal processing circuit 1000 may includescramblers 1010, modulators 1020, a layer mapper 1030, a precoder 1040,resource mappers 1050, and signal generators 1060. An operation/functionof FIG. 21 may be performed, without being limited to, the processors102 and 202 and/or the transceivers 106 and 206 of FIG. 20 . Hardwareelements of FIG. 21 may be implemented by the processors 102 and 202and/or the transceivers 106 and 206 of FIG. 20 . For example, blocks1010 to 1060 may be implemented by the processors 102 and 202 of FIG. 20. Alternatively, the blocks 1010 to 1050 may be implemented by theprocessors 102 and 202 of FIG. 20 and the block 1060 may be implementedby the transceivers 106 and 206 of FIG. 20 .

Codewords may be converted into radio signals via the signal processingcircuit 1000 of FIG. 21 . Herein, the codewords are encoded bitsequences of information blocks. The information blocks may includetransport blocks (e.g., a UL-SCH transport block, a DL-SCH transportblock). The radio signals may be transmitted through various physicalchannels (e.g., a PUSCH and a PDSCH).

Specifically, the codewords may be converted into scrambled bitsequences by the scramblers 1010. Scramble sequences used for scramblingmay be generated based on an initialization value, and theinitialization value may include ID information of a wireless device.The scrambled bit sequences may be modulated to modulation symbolsequences by the modulators 1020. A modulation scheme may includepi/2-Binary Phase Shift Keying (pi/2-BPSK), m-Phase Shift Keying(m-PSK), and m-Quadrature Amplitude Modulation (m-QAM). Complexmodulation symbol sequences may be mapped to one or more transportlayers by the layer mapper 1030. Modulation symbols of each transportlayer may be mapped (precoded) to corresponding antenna port(s) by theprecoder 1040. Outputs z of the precoder 1040 may be obtained bymultiplying outputs y of the layer mapper 1030 by an N*M precodingmatrix W. Herein, N is the number of antenna ports and M is the numberof transport layers. The precoder 1040 may perform precoding afterperforming transform precoding (e.g., DFT) for complex modulationsymbols. Alternatively, the precoder 1040 may perform precoding withoutperforming transform precoding.

The resource mappers 1050 may map modulation symbols of each antennaport to time-frequency resources. The time-frequency resources mayinclude a plurality of symbols (e.g., a CP-OFDMA symbols and DFT-s-OFDMAsymbols) in the time domain and a plurality of subcarriers in thefrequency domain. The signal generators 1060 may generate radio signalsfrom the mapped modulation symbols and the generated radio signals maybe transmitted to other devices through each antenna. For this purpose,the signal generators 1060 may include Inverse Fast Fourier Transform(IFFT) modules, Cyclic Prefix (CP) inserters, Digital-to-AnalogConverters (DACs), and frequency up-converters.

Signal processing procedures for a signal received in the wirelessdevice may be configured in a reverse manner of the signal processingprocedures 1010 to 1060 of FIG. 21 . For example, the wireless devices(e.g., 100 and 200 of FIG. 20 ) may receive radio signals from theexterior through the antenna ports/transceivers. The received radiosignals may be converted into baseband signals through signal restorers.To this end, the signal restorers may include frequency downlinkconverters, Analog-to-Digital Converters (ADCs), CP remover, and FastFourier Transform (FFT) modules. Next, the baseband signals may berestored to codewords through a resource demapping procedure, apostcoding procedure, a demodulation processor, and a descramblingprocedure. The codewords may be restored to original information blocksthrough decoding. Therefore, a signal processing circuit (notillustrated) for a reception signal may include signal restorers,resource demappers, a postcoder, demodulators, descramblers, anddecoders.

FIG. 22 shows another example of a wireless device, based on anembodiment of the present disclosure. The wireless device may beimplemented in various forms according to a use-case/service (refer toFIG. 19 ). The embodiment of FIG. 22 may be combined with variousembodiments of the present disclosure.

Referring to FIG. 22 , wireless devices 100 and 200 may correspond tothe wireless devices 100 and 200 of FIG. 20 and may be configured byvarious elements, components, units/portions, and/or modules. Forexample, each of the wireless devices 100 and 200 may include acommunication unit 110, a control unit 120, a memory unit 130, andadditional components 140. The communication unit may include acommunication circuit 112 and transceiver(s) 114. For example, thecommunication circuit 112 may include the one or more processors 102 and202 and/or the one or more memories 104 and 204 of FIG. 20 . Forexample, the transceiver(s) 114 may include the one or more transceivers106 and 206 and/or the one or more antennas 108 and 208 of FIG. 20 . Thecontrol unit 120 is electrically connected to the communication unit110, the memory 130, and the additional components 140 and controlsoverall operation of the wireless devices. For example, the control unit120 may control an electric/mechanical operation of the wireless devicebased on programs/code/commands/information stored in the memory unit130. The control unit 120 may transmit the information stored in thememory unit 130 to the exterior (e.g., other communication devices) viathe communication unit 110 through a wireless/wired interface or store,in the memory unit 130, information received through the wireless/wiredinterface from the exterior (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be variously configured according totypes of wireless devices. For example, the additional components 140may include at least one of a power unit/battery, input/output (I/O)unit, a driving unit, and a computing unit. The wireless device may beimplemented in the form of, without being limited to, the robot (100 aof FIG. 19 ), the vehicles (100 b-1 and 100 b-2 of FIG. 19 ), the XRdevice (100 c of FIG. 19 ), the hand-held device (100 d of FIG. 19 ),the home appliance (100 e of FIG. 19 ), the IoT device (100 f of FIG. 19), a digital broadcast terminal, a hologram device, a public safetydevice, an MTC device, a medicine device, a fintech device (or a financedevice), a security device, a climate/environment device, the AIserver/device (400 of FIG. 19 ), the BSs (200 of FIG. 19 ), a networknode, etc. The wireless device may be used in a mobile or fixed placeaccording to a use-example/service.

In FIG. 22 , the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wirelessly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor, an Electronic Control Unit (ECU), agraphical processing unit, and a memory control processor. As anotherexample, the memory 130 may be configured by a Random Access Memory(RAM), a Dynamic RAM (DRAM), a Read Only Memory (ROM)), a flash memory,a volatile memory, a non-volatile memory, and/or a combination thereof.

Hereinafter, an example of implementing FIG. 22 will be described indetail with reference to the drawings.

FIG. 23 shows a hand-held device, based on an embodiment of the presentdisclosure. The hand-held device may include a smartphone, a smartpad, awearable device (e.g., a smartwatch or a smartglasses), or a portablecomputer (e.g., a notebook). The hand-held device may be referred to asa mobile station (MS), a user terminal (UT), a Mobile Subscriber Station(MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), or aWireless Terminal (WT). The embodiment of FIG. 23 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 23 , a hand-held device 100 may include an antennaunit 108, a communication unit 110, a control unit 120, a memory unit130, a power supply unit 140 a, an interface unit 140 b, and an I/O unit140 c. The antenna unit 108 may be configured as a part of thecommunication unit 110. Blocks 110 to 130/140 a to 140 c correspond tothe blocks 110 to 130/140 of FIG. 22 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from other wireless devices or BSs. Thecontrol unit 120 may perform various operations by controllingconstituent elements of the hand-held device 100. The control unit 120may include an Application Processor (AP). The memory unit 130 may storedata/parameters/programs/code/commands needed to drive the hand-helddevice 100. The memory unit 130 may store input/output data/information.The power supply unit 140 a may supply power to the hand-held device 100and include a wired/wireless charging circuit, a battery, etc. Theinterface unit 140 b may support connection of the hand-held device 100to other external devices. The interface unit 140 b may include variousports (e.g., an audio I/O port and a video I/O port) for connection withexternal devices. The I/O unit 140 c may input or output videoinformation/signals, audio information/signals, data, and/or informationinput by a user. The I/O unit 140 c may include a camera, a microphone,a user input unit, a display unit 140 d, a speaker, and/or a hapticmodule.

As an example, in the case of data communication, the I/O unit 140 c mayacquire information/signals (e.g., touch, text, voice, images, or video)input by a user and the acquired information/signals may be stored inthe memory unit 130. The communication unit 110 may convert theinformation/signals stored in the memory into radio signals and transmitthe converted radio signals to other wireless devices directly or to aBS. The communication unit 110 may receive radio signals from otherwireless devices or the BS and then restore the received radio signalsinto original information/signals. The restored information/signals maybe stored in the memory unit 130 and may be output as various types(e.g., text, voice, images, video, or haptic) through the I/O unit 140c.

FIG. 24 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure. The vehicle or autonomous vehicle may beimplemented by a mobile robot, a car, a train, a manned/unmanned AerialVehicle (AV), a ship, etc. The embodiment of FIG. 24 may be combinedwith various embodiments of the present disclosure.

Referring to FIG. 24 , a vehicle or autonomous vehicle 100 may includean antenna unit 108, a communication unit 110, a control unit 120, adriving unit 140 a, a power supply unit 140 b, a sensor unit 140 c, andan autonomous driving unit 140 d. The antenna unit 108 may be configuredas a part of the communication unit 110. The blocks 110/130/140 a to 140d correspond to the blocks 110/130/140 of FIG. 22 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous vehicle 100. The control unit 120 may includean Electronic Control Unit (ECU). The driving unit 140 a may cause thevehicle or the autonomous vehicle 100 to drive on a road. The drivingunit 140 a may include an engine, a motor, a powertrain, a wheel, abrake, a steering device, etc. The power supply unit 140 b may supplypower to the vehicle or the autonomous vehicle 100 and include awired/wireless charging circuit, a battery, etc. The sensor unit 140 cmay acquire a vehicle state, ambient environment information, userinformation, etc. The sensor unit 140 c may include an InertialMeasurement Unit (IMU) sensor, a collision sensor, a wheel sensor, aspeed sensor, a slope sensor, a weight sensor, a heading sensor, aposition module, a vehicle forward/backward sensor, a battery sensor, afuel sensor, a tire sensor, a steering sensor, a temperature sensor, ahumidity sensor, an ultrasonic sensor, an illumination sensor, a pedalposition sensor, etc. The autonomous driving unit 140 d may implementtechnology for maintaining a lane on which a vehicle is driving,technology for automatically adjusting speed, such as adaptive cruisecontrol, technology for autonomously driving along a determined path,technology for driving by automatically setting a path if a destinationis set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, etc. from an external server. The autonomous drivingunit 140 d may generate an autonomous driving path and a driving planfrom the obtained data. The control unit 120 may control the drivingunit 140 a such that the vehicle or the autonomous vehicle 100 may movealong the autonomous driving path according to the driving plan (e.g.,speed/direction control). In the middle of autonomous driving, thecommunication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. In themiddle of autonomous driving, the sensor unit 140 c may obtain a vehiclestate and/or surrounding environment information. The autonomous drivingunit 140 d may update the autonomous driving path and the driving planbased on the newly obtained data/information. The communication unit 110may transfer information about a vehicle position, the autonomousdriving path, and/or the driving plan to the external server. Theexternal server may predict traffic information data using AItechnology, etc., based on the information collected from vehicles orautonomous vehicles and provide the predicted traffic information datato the vehicles or the autonomous vehicles.

Claims in the present description can be combined in a various way. Forinstance, technical features in method claims of the present descriptioncan be combined to be implemented or performed in an apparatus, andtechnical features in apparatus claims can be combined to be implementedor performed in a method. Further, technical features in method claim(s)and apparatus claim(s) can be combined to be implemented or performed inan apparatus. Further, technical features in method claim(s) andapparatus claim(s) can be combined to be implemented or performed in amethod.

What is claimed is:
 1. A method for performing wireless communication bya first device, the method comprising: obtaining configurationinformation including at least one of information related to a firstfixed frame period (FFP) or information related to a first FFP offset;determining a plurality of FFPs based on the configuration information;performing sensing related to the plurality of FFPs; determining whethera channel is idle within the plurality of FFPs based on the sensingrelated to the plurality of FFPs; and transmitting information relatedto a failure of the configuration information, based on a number ofnon-idle channels reaching a threshold.
 2. The method of claim 1,wherein the configuration information is received from a base station,and the information related to the failure of the configurationinformation is transmitted to the base station.
 3. The method of claim2, further comprising: receiving, from the base station, reconfigurationinformation including at least one of information related to a secondFFP or information related to a second FFP offset, in response to theinformation related to the failure of the configuration information. 4.The method of claim 2, further comprising: receiving, from the basestation, information for load based equipment (LBE)-based unlicensedband communication, in response to the information related to thefailure of the configuration information.
 5. The method of claim 4,wherein, based on the information for the LBE-based unlicensed bandcommunication, a sensing operation in units of a fixed frame based onthe configuration information is stopped.
 6. The method of claim 1,wherein the configuration information is received from a second device,and the information related to the failure of the configurationinformation is transmitted to the second device.
 7. The method of claim6, further comprising: receiving, from the second device,reconfiguration information including at least one of informationrelated to a second FFP or information related to a second FFP offset,in response to the information related to the failure of theconfiguration information.
 8. The method of claim 7, further comprising:transmitting the reconfiguration information to a serving base stationof the first device.
 9. The method of claim 1, wherein the first deviceperforms sidelink (SL) communication in an unlicensed band based on theconfiguration information, after transmitting the information related tothe failure of the configuration information and before receivingreconfiguration information or information for load based equipment(LBE)-based unlicensed band communication.
 10. The method of claim 1,further comprising: transmitting, to at least one device, informationrepresenting that FFP-based unlicensed band communication is performedor information representing that load based equipment (LBE)-basedunlicensed band communication is performed.
 11. The method of claim 1,wherein the sensing related to the plurality of FFPs is performed duringeach time duration before a start of each of the plurality of FFPs. 12.The method of claim 1, wherein the threshold is configured for the firstdevice based on a channel access priority class (CAPC) or for eachresource pool.
 13. The method of claim 1, wherein the configurationinformation is determined by the first device.
 14. A first deviceadapted to perform wireless communication, the first device comprising:at least one transceiver; at least one processor; and at least onememory connected to the at least one processor and storing instructionsthat, based on being executed by the at least one processor, performoperations comprising: obtaining configuration information including atleast one of information related to a first fixed frame period (FFP) orinformation related to a first FFP offset; determining a plurality ofFFPs based on the configuration information; performing sensing relatedto the plurality of FFPs; determining whether a channel is idle withinthe plurality of FFPs based on the sensing related to the plurality ofFFPs; and transmitting information related to a failure of theconfiguration information, based on a number of non-idle channelsreaching a threshold.
 15. A processing device adapted to control a firstdevice, the processing device comprising: at least one processor; and atleast one memory connected to the at least one processor and storinginstructions that, based on being executed by the at least oneprocessor, perform operations comprising: obtaining configurationinformation including at least one of information related to a firstfixed frame period (FFP) or information related to a first FFP offset;determining a plurality of FFPs based on the configuration information;performing sensing related to the plurality of FFPs; determining whethera channel is idle within the plurality of FFPs based on the sensingrelated to the plurality of FFPs; and transmitting information relatedto a failure of the configuration information, based on a number ofnon-idle channels reaching a threshold.
 16. The processing device ofclaim 15, wherein the configuration information is received from a basestation, and the information related to the failure of the configurationinformation is transmitted to the base station.
 17. The processingdevice of claim 16, wherein the operations further comprise: receiving,from the base station, reconfiguration information including at leastone of information related to a second FFP or information related to asecond FFP offset, in response to the information related to the failureof the configuration information.
 18. The processing device of claim 16,wherein the operations further comprise: receiving, from the basestation, information for load based equipment (LBE)-based unlicensedband communication, in response to the information related to thefailure of the configuration information.
 19. The processing device ofclaim 18, wherein, based on the information for the LBE-based unlicensedband communication, a sensing operation in units of a fixed frame basedon the configuration information is stopped.
 20. The processing deviceof claim 15, wherein the first device performs sidelink (SL)communication in an unlicensed band based on the configurationinformation, after transmitting the information related to the failureof the configuration information and before receiving reconfigurationinformation or information for load based equipment (LBE)-basedunlicensed band communication.